diff --git a/src/nvim/drawline.c b/src/nvim/drawline.c
index eef427a7b8..e5d2ba7550 100644
--- a/src/nvim/drawline.c
+++ b/src/nvim/drawline.c
@@ -3330,5 +3330,6 @@ static void win_put_linebuf(win_T *wp, int row, int coloff, int endcol, int clea
     }
   }
 
+  grid_adjust(&grid, &row, &coloff);
   grid_put_linebuf(grid, row, coloff, 0, endcol, clear_width, wp->w_p_rl, bg_attr, wrap, false);
 }
diff --git a/src/nvim/drawscreen.c b/src/nvim/drawscreen.c
index a0cbc60f25..e32a556daa 100644
--- a/src/nvim/drawscreen.c
+++ b/src/nvim/drawscreen.c
@@ -2382,26 +2382,20 @@ static void win_update(win_T *wp, DecorProviders *providers)
       wp->w_botline = lnum;
       wp->w_filler_rows = wp->w_grid.rows - srow;
     } else if (dy_flags & DY_TRUNCATE) {      // 'display' has "truncate"
-      int scr_row = wp->w_grid.rows - 1;
-      int symbol = wp->w_p_fcs_chars.lastline;
-      char fillbuf[12];  // 2 characters of 6 bytes
-      int charlen = utf_char2bytes(symbol, &fillbuf[0]);
-      utf_char2bytes(symbol, &fillbuf[charlen]);
-
       // Last line isn't finished: Display "@@@" in the last screen line.
-      grid_puts(&wp->w_grid, fillbuf, MIN(wp->w_grid.cols, 2) * charlen, scr_row, 0, at_attr);
-      grid_fill(&wp->w_grid, scr_row, scr_row + 1, 2, wp->w_grid.cols, symbol, ' ', at_attr);
+      grid_line_start(&wp->w_grid, wp->w_grid.rows - 1);
+      grid_line_fill(0, MIN(wp->w_grid.cols, 3), wp->w_p_fcs_chars.lastline, at_attr);
+      grid_line_fill(3, wp->w_grid.cols, ' ', at_attr);
+      grid_line_flush();
       set_empty_rows(wp, srow);
       wp->w_botline = lnum;
     } else if (dy_flags & DY_LASTLINE) {      // 'display' has "lastline"
-      int start_col = wp->w_grid.cols - 3;
-      int symbol = wp->w_p_fcs_chars.lastline;
-
       // Last line isn't finished: Display "@@@" at the end.
       // TODO(bfredl): this display ">@@@" when ">" was a left-halve
       // maybe "@@@@" is preferred when this happens.
       grid_line_start(&wp->w_grid, wp->w_grid.rows - 1);
-      grid_line_fill(MAX(start_col, 0), wp->w_grid.cols, symbol, at_attr);
+      grid_line_fill(MAX(wp->w_grid.cols - 3, 0), wp->w_grid.cols,
+                     wp->w_p_fcs_chars.lastline, at_attr);
       grid_line_flush();
       set_empty_rows(wp, srow);
       wp->w_botline = lnum;
diff --git a/src/nvim/edit.c b/src/nvim/edit.c
index 58cface37f..4593748c25 100644
--- a/src/nvim/edit.c
+++ b/src/nvim/edit.c
@@ -1412,11 +1412,11 @@ static void ins_ctrl_v(void)
 // Put a character directly onto the screen.  It's not stored in a buffer.
 // Used while handling CTRL-K, CTRL-V, etc. in Insert mode.
 static int pc_status;
-#define PC_STATUS_UNSET 0       // pc_bytes was not set
-#define PC_STATUS_RIGHT 1       // right half of double-wide char
-#define PC_STATUS_LEFT  2       // left half of double-wide char
-#define PC_STATUS_SET   3       // pc_bytes was filled
-static char pc_bytes[MB_MAXBYTES + 1];  // saved bytes
+#define PC_STATUS_UNSET 0  // nothing was put on screen
+#define PC_STATUS_RIGHT 1  // right half of double-wide char
+#define PC_STATUS_LEFT  2  // left half of double-wide char
+#define PC_STATUS_SET   3  // pc_schar was filled
+static schar_T pc_schar;   // saved char
 static int pc_attr;
 static int pc_row;
 static int pc_col;
@@ -1433,31 +1433,34 @@ void edit_putchar(int c, bool highlight)
       attr = 0;
     }
     pc_row = curwin->w_wrow;
-    pc_col = 0;
     pc_status = PC_STATUS_UNSET;
+    grid_line_start(&curwin->w_grid, pc_row);
     if (curwin->w_p_rl) {
-      pc_col += curwin->w_grid.cols - 1 - curwin->w_wcol;
-      const int fix_col = grid_fix_col(&curwin->w_grid, pc_col, pc_row);
+      pc_col = curwin->w_grid.cols - 1 - curwin->w_wcol;
 
-      if (fix_col != pc_col) {
-        grid_putchar(&curwin->w_grid, ' ', pc_row, fix_col, attr);
+      if (grid_line_getchar(pc_col, NULL) == NUL) {
+        grid_line_put_schar(pc_col - 1, schar_from_ascii(' '), attr);
         curwin->w_wcol--;
         pc_status = PC_STATUS_RIGHT;
       }
     } else {
-      pc_col += curwin->w_wcol;
-      if (grid_lefthalve(&curwin->w_grid, pc_row, pc_col)) {
+      pc_col = curwin->w_wcol;
+
+      if (grid_line_getchar(pc_col + 1, NULL) == NUL) {
+        // pc_col is the left half of a double-width char
         pc_status = PC_STATUS_LEFT;
       }
     }
 
     // save the character to be able to put it back
     if (pc_status == PC_STATUS_UNSET) {
-      // TODO(bfredl): save the schar_T instead
-      grid_getbytes(&curwin->w_grid, pc_row, pc_col, pc_bytes, &pc_attr);
+      pc_schar = grid_line_getchar(pc_col, &pc_attr);
       pc_status = PC_STATUS_SET;
     }
-    grid_putchar(&curwin->w_grid, c, pc_row, pc_col, attr);
+
+    char buf[MB_MAXBYTES + 1];
+    grid_line_puts(pc_col, buf, utf_char2bytes(c, buf), attr);
+    grid_line_flush();
   }
 }
 
@@ -1537,7 +1540,10 @@ void edit_unputchar(void)
     if (pc_status == PC_STATUS_RIGHT || pc_status == PC_STATUS_LEFT) {
       redrawWinline(curwin, curwin->w_cursor.lnum);
     } else {
-      grid_puts(&curwin->w_grid, pc_bytes, -1, pc_row, pc_col, pc_attr);
+      // TODO(bfredl): this could be smarter and also handle the dubyawidth case
+      grid_line_start(&curwin->w_grid, pc_row);
+      grid_line_put_schar(pc_col, pc_schar, pc_attr);
+      grid_line_flush();
     }
   }
 }
diff --git a/src/nvim/eval/funcs.c b/src/nvim/eval/funcs.c
index 4dd3f193e6..eb2e2fb1e2 100644
--- a/src/nvim/eval/funcs.c
+++ b/src/nvim/eval/funcs.c
@@ -6885,7 +6885,7 @@ static void f_screenchar(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     c = -1;
   } else {
     char buf[MB_MAXBYTES + 1];
-    grid_getbytes(grid, row, col, buf, NULL);
+    schar_get(buf, grid_getchar(grid, row, col, NULL));
     c = utf_ptr2char(buf);
   }
   rettv->vval.v_number = c;
@@ -6906,7 +6906,7 @@ static void f_screenchars(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   }
 
   char buf[MB_MAXBYTES + 1];
-  grid_getbytes(grid, row, col, buf, NULL);
+  schar_get(buf, grid_getchar(grid, row, col, NULL));
   int pcc[MAX_MCO];
   int c = utfc_ptr2char(buf, pcc);
   int composing_len = 0;
@@ -6951,7 +6951,7 @@ static void f_screenstring(typval_T *argvars, typval_T *rettv, EvalFuncData fptr
   }
 
   char buf[MB_MAXBYTES + 1];
-  grid_getbytes(grid, row, col, buf, NULL);
+  schar_get(buf, grid_getchar(grid, row, col, NULL));
   rettv->vval.v_string = xstrdup(buf);
 }
 
diff --git a/src/nvim/grid.c b/src/nvim/grid.c
index 7a707407d2..2eab158bc4 100644
--- a/src/nvim/grid.c
+++ b/src/nvim/grid.c
@@ -201,65 +201,23 @@ static bool grid_invalid_row(ScreenGrid *grid, int row)
   return grid->attrs[grid->line_offset[row]] < 0;
 }
 
-/// Return number of display cells for char at grid->chars[off].
-/// We make sure that the offset used is less than "max_off".
-static int grid_off2cells(ScreenGrid *grid, size_t off, size_t max_off)
-{
-  return (off + 1 < max_off && grid->chars[off + 1] == 0) ? 2 : 1;
-}
-
-/// Return true if the character at "row"/"col" on the screen is the left side
-/// of a double-width character.
-///
-/// Caller must make sure "row" and "col" are not invalid!
-bool grid_lefthalve(ScreenGrid *grid, int row, int col)
-{
-  grid_adjust(&grid, &row, &col);
-
-  return grid_off2cells(grid, grid->line_offset[row] + (size_t)col,
-                        grid->line_offset[row] + (size_t)grid->cols) > 1;
-}
-
-/// Correct a position on the screen, if it's the right half of a double-wide
-/// char move it to the left half.  Returns the corrected column.
-int grid_fix_col(ScreenGrid *grid, int col, int row)
-{
-  int coloff = 0;
-  grid_adjust(&grid, &row, &coloff);
-
-  col += coloff;
-  if (grid->chars != NULL && col > 0
-      && grid->chars[grid->line_offset[row] + (size_t)col] == 0) {
-    return col - 1 - coloff;
-  }
-  return col - coloff;
-}
-
-/// output a single character directly to the grid
-void grid_putchar(ScreenGrid *grid, int c, int row, int col, int attr)
-{
-  char buf[MB_MAXBYTES + 1];
-
-  grid_puts(grid, buf, utf_char2bytes(c, buf), row, col, attr);
-}
-
 /// Get a single character directly from grid.chars into "bytes", which must
 /// have a size of "MB_MAXBYTES + 1".
 /// If "attrp" is not NULL, return the character's attribute in "*attrp".
-void grid_getbytes(ScreenGrid *grid, int row, int col, char *bytes, int *attrp)
+schar_T grid_getchar(ScreenGrid *grid, int row, int col, int *attrp)
 {
   grid_adjust(&grid, &row, &col);
 
   // safety check
   if (grid->chars == NULL || row >= grid->rows || col >= grid->cols) {
-    return;
+    return NUL;
   }
 
   size_t off = grid->line_offset[row] + (size_t)col;
   if (attrp != NULL) {
     *attrp = grid->attrs[off];
   }
-  schar_get(bytes, grid->chars[off]);
+  return grid->chars[off];
 }
 
 static ScreenGrid *grid_line_grid = NULL;
@@ -269,38 +227,6 @@ static int grid_line_maxcol = 0;
 static int grid_line_first = INT_MAX;
 static int grid_line_last = 0;
 
-/// put string 'text' on the window grid at position 'row' and 'col', with
-/// attributes 'attr', and update contents of 'grid'
-/// @param textlen length of string or -1 to use strlen(text)
-/// Note: only outputs within one row!
-int grid_puts(ScreenGrid *grid, const char *text, int textlen, int row, int col, int attr)
-{
-  grid_line_start(grid, row);
-
-  // Safety check. The check for negative row and column is to fix issue
-  // vim/vim#4102. TODO(neovim): find out why row/col could be negative.
-  int off_col = grid_line_coloff + col;
-  if (grid_line_grid->chars == NULL
-      || grid_line_row >= grid_line_grid->rows || grid_line_row < 0
-      || off_col >= grid_line_grid->cols || off_col < 0) {
-    if (rdb_flags & RDB_INVALID) {
-      abort();
-    } else {
-      grid_line_grid = NULL;
-      return 0;
-    }
-  }
-
-  int len = grid_line_puts(col, text, textlen, attr);
-  if (grid_line_last > grid_line_first) {
-    // TODO(bfredl): this is bullshit. message.c should manage its own cursor movements
-    int col_pos = MIN(grid_line_coloff + grid_line_last, grid_line_grid->cols - 1);
-    ui_grid_cursor_goto(grid_line_grid->handle, grid_line_row, col_pos);
-  }
-  grid_line_flush();
-  return len;
-}
-
 /// Start a group of grid_line_puts calls that builds a single grid line.
 ///
 /// Must be matched with a grid_line_flush call before moving to
@@ -318,6 +244,25 @@ void grid_line_start(ScreenGrid *grid, int row)
   grid_line_last = 0;
 }
 
+/// Get present char from current rendered screen line
+///
+/// This indicates what already is on screen, not the pending render buffer.
+///
+/// @return char or space if out of bounds
+schar_T grid_line_getchar(int col, int *attr)
+{
+  if (col < grid_line_maxcol) {
+    size_t off = grid_line_grid->line_offset[grid_line_row] + (size_t)col;
+    if (attr != NULL) {
+      *attr = grid_line_grid->attrs[off];
+    }
+    return grid_line_grid->chars[off];
+  } else {
+    // NUL is a very special value (right-half of double width), space is True Neutral™
+    return schar_from_ascii(' ');
+  }
+}
+
 void grid_line_put_schar(int col, schar_T schar, int attr)
 {
   assert(grid_line_grid);
@@ -331,8 +276,13 @@ void grid_line_put_schar(int col, schar_T schar, int attr)
   linebuf_vcol[col] = -1;
 }
 
-/// like grid_puts(), but output "text[len]".  When "len" is -1 output up to
-/// a NUL.
+/// Put string "text" at "col" position relative to the grid line from the
+/// recent grid_line_start() call.
+///
+/// @param textlen length of string or -1 to use strlen(text)
+/// Note: only outputs within one row!
+///
+/// @return number of grid cells used
 int grid_line_puts(int col, const char *text, int textlen, int attr)
 {
   const char *ptr = text;
@@ -435,8 +385,16 @@ void grid_line_fill(int start_col, int end_col, int c, int attr)
     linebuf_attr[col] = attr;
     linebuf_vcol[col] = -1;
   }
-  grid_line_first = MIN(grid_line_first, start_col);
-  grid_line_last = MAX(grid_line_last, end_col);
+  if (start_col < end_col) {
+    grid_line_first = MIN(grid_line_first, start_col);
+    grid_line_last = MAX(grid_line_last, end_col);
+  }
+}
+
+/// move the cursor to a position in a currently rendered line.
+void grid_line_cursor_goto(int col)
+{
+  ui_grid_cursor_goto(grid_line_grid->handle, grid_line_row, col);
 }
 
 /// End a group of grid_line_puts calls and send the screen buffer to the UI layer.
@@ -500,27 +458,29 @@ void grid_fill(ScreenGrid *grid, int start_row, int end_row, int start_col, int
   }
 
   for (int row = start_row; row < end_row; row++) {
+    int dirty_first = INT_MAX;
+    int dirty_last = 0;
+    size_t lineoff = grid->line_offset[row];
+
     // When drawing over the right half of a double-wide char clear
     // out the left half.  When drawing over the left half of a
     // double wide-char clear out the right half.  Only needed in a
     // terminal.
-    if (start_col > 0 && grid_fix_col(grid, start_col, row) != start_col) {
-      grid_puts(grid, " ", 1, row, start_col - 1, 0);
+    if (start_col > 0 && grid->chars[lineoff + (size_t)start_col] == NUL) {
+      size_t off = lineoff + (size_t)start_col - 1;
+      grid->chars[off] = schar_from_ascii(' ');
+      grid->attrs[off] = attr;
+      dirty_first = start_col - 1;
     }
-    if (end_col < grid->cols
-        && grid_fix_col(grid, end_col, row) != end_col) {
-      grid_puts(grid, " ", 1, row, end_col, 0);
+    if (end_col < grid->cols && grid->chars[lineoff + (size_t)end_col] == NUL) {
+      size_t off = lineoff + (size_t)end_col;
+      grid->chars[off] = schar_from_ascii(' ');
+      grid->attrs[off] = attr;
+      dirty_last = end_col + 1;
     }
 
-    // if grid was resized (in ext_multigrid mode), the UI has no redraw updates
-    // for the newly resized grid. It is better mark everything as dirty and
-    // send all the updates.
-    int dirty_first = INT_MAX;
-    int dirty_last = 0;
-
     int col = start_col;
     sc = schar_from_char(c1);
-    size_t lineoff = grid->line_offset[row];
     for (col = start_col; col < end_col; col++) {
       size_t off = lineoff + (size_t)col;
       if (grid->chars[off] != sc || grid->attrs[off] != attr || rdb_flags & RDB_NODELTA) {
@@ -600,8 +560,6 @@ void grid_put_linebuf(ScreenGrid *grid, int row, int coloff, int col, int endcol
     endcol = grid->cols;
   }
 
-  grid_adjust(&grid, &row, &coloff);
-
   // Safety check. Avoids clang warnings down the call stack.
   if (grid->chars == NULL || row >= grid->rows || coloff >= grid->cols) {
     DLOG("invalid state, skipped");
@@ -662,12 +620,8 @@ void grid_put_linebuf(ScreenGrid *grid, int row, int coloff, int col, int endcol
       // the right half of the old character.
       // Also required when writing the right half of a double-width
       // char over the left half of an existing one
-      if (col + char_cells == endcol
-          && ((char_cells == 1
-               && grid_off2cells(grid, off, max_off_to) > 1)
-              || (char_cells == 2
-                  && grid_off2cells(grid, off, max_off_to) == 1
-                  && grid_off2cells(grid, off + 1, max_off_to) > 1))) {
+      if (col + char_cells == endcol && off + (size_t)char_cells < max_off_to
+          && grid->chars[off + (size_t)char_cells] == NUL) {
         clear_next = true;
       }
 
diff --git a/src/nvim/message.c b/src/nvim/message.c
index 97402276b2..67266b325c 100644
--- a/src/nvim/message.c
+++ b/src/nvim/message.c
@@ -2959,15 +2959,15 @@ void os_msg(const char *str)
 
 void msg_moremsg(int full)
 {
-  int attr;
-  char *s = _("-- More --");
-
-  attr = hl_combine_attr(HL_ATTR(HLF_MSG), HL_ATTR(HLF_M));
-  grid_puts(&msg_grid_adj, s, -1, Rows - 1, 0, attr);
+  int attr = hl_combine_attr(HL_ATTR(HLF_MSG), HL_ATTR(HLF_M));
+  grid_line_start(&msg_grid_adj, Rows - 1);
+  int len = grid_line_puts(0, _("-- More --"), -1, attr);
   if (full) {
-    grid_puts(&msg_grid_adj, _(" SPACE/d/j: screen/page/line down, b/u/k: up, q: quit "), -1,
-              Rows - 1, vim_strsize(s), attr);
+    len += grid_line_puts(len, _(" SPACE/d/j: screen/page/line down, b/u/k: up, q: quit "),
+                          -1, attr);
   }
+  grid_line_cursor_goto(len);
+  grid_line_flush();
 }
 
 /// Repeat the message for the current mode: MODE_ASKMORE, MODE_EXTERNCMD,
diff --git a/src/nvim/statusline.c b/src/nvim/statusline.c
index 1529b63812..fb467093ad 100644
--- a/src/nvim/statusline.c
+++ b/src/nvim/statusline.c
@@ -182,7 +182,9 @@ void win_redr_status(win_T *wp)
       attr = win_hl_attr(wp, HLF_C);
       fillchar = wp->w_p_fcs_chars.vert;
     }
-    grid_putchar(&default_grid, fillchar, W_ENDROW(wp), W_ENDCOL(wp), attr);
+    grid_line_start(&default_grid, W_ENDROW(wp));
+    grid_line_put_schar(W_ENDCOL(wp), schar_from_char(fillchar), attr);
+    grid_line_flush();
   }
   busy = false;
 }
diff --git a/src/nvim/ui_compositor.c b/src/nvim/ui_compositor.c
index 0f26e269ae..8c16380f1f 100644
--- a/src/nvim/ui_compositor.c
+++ b/src/nvim/ui_compositor.c
@@ -532,7 +532,7 @@ void ui_comp_raw_line(Integer grid, Integer row, Integer startcol, Integer endco
     compose_debug(row, row + 1, startcol, clearcol, dbghl_composed, true);
     compose_line(row, startcol, clearcol, flags);
   } else {
-    compose_debug(row, row + 1, startcol, endcol, dbghl_normal, false);
+    compose_debug(row, row + 1, startcol, endcol, dbghl_normal, endcol >= clearcol);
     compose_debug(row, row + 1, endcol, clearcol, dbghl_clear, true);
 #ifndef NDEBUG
     for (int i = 0; i < endcol - startcol; i++) {
diff --git a/src/nvim/version.c b/src/nvim/version.c
index 20bbcb2f8a..c3bfad4706 100644
--- a/src/nvim/version.c
+++ b/src/nvim/version.c
@@ -2827,7 +2827,7 @@ void intro_message(int colon)
       }
 
       if (*mesg != NUL) {
-        do_intro_line(row, mesg, 0);
+        do_intro_line((int)row, mesg, 0);
       }
       row++;
 
@@ -2838,14 +2838,13 @@ void intro_message(int colon)
   }
 }
 
-static void do_intro_line(long row, char *mesg, int attr)
+static void do_intro_line(int row, char *mesg, int attr)
 {
   char *p;
   int l;
-  int clen;
 
   // Center the message horizontally.
-  long col = vim_strsize(mesg);
+  int col = vim_strsize(mesg);
 
   col = (Columns - col) / 2;
 
@@ -2853,21 +2852,18 @@ static void do_intro_line(long row, char *mesg, int attr)
     col = 0;
   }
 
+  grid_line_start(&default_grid, row);
   // Split up in parts to highlight <> items differently.
   for (p = mesg; *p != NUL; p += l) {
-    clen = 0;
-
     for (l = 0;
          p[l] != NUL && (l == 0 || (p[l] != '<' && p[l - 1] != '>'));
          l++) {
-      clen += ptr2cells(p + l);
       l += utfc_ptr2len(p + l) - 1;
     }
     assert(row <= INT_MAX && col <= INT_MAX);
-    grid_puts(&default_grid, p, l, (int)row, (int)col,
-              *p == '<' ? HL_ATTR(HLF_8) : attr);
-    col += clen;
+    col += grid_line_puts(col, p, l, *p == '<' ? HL_ATTR(HLF_8) : attr);
   }
+  grid_line_flush();
 }
 
 /// ":intro": clear screen, display intro screen and wait for return.
diff --git a/test/functional/ui/messages_spec.lua b/test/functional/ui/messages_spec.lua
index 46a42e5beb..8a13796c04 100644
--- a/test/functional/ui/messages_spec.lua
+++ b/test/functional/ui/messages_spec.lua
@@ -1366,7 +1366,7 @@ describe('ui/ext_messages', function()
 
     feed(":intro<cr>")
     screen:expect{grid=[[
-                                                                                      |
+      ^                                                                                |
                                                                                       |
                                                                                       |
                                                                                       |