ui: Fix click on foldcolumn when ext_multigrid is enabled

src/nvim/mouse.c

@@ -75,6 +75,7 @@ int jump_to_mouse(int flags,
   int grid = mouse_grid;
   int mouse_char;
   int fdc = 0;
+  ScreenGrid *gp = &default_grid;
 
   mouse_past_bottom = false;
   mouse_past_eol = false;
@@ -125,16 +126,6 @@ retnomove:
   if (flags & MOUSE_SETPOS)
     goto retnomove;                             // ugly goto...
 
-  // Remember the character under the mouse, might be one of foldclose or
-  // foldopen fillchars in the fold column.
-  if (row >= 0 && row < Rows && col >= 0 && col <= Columns
-      && default_grid.chars != NULL) {
-     mouse_char = utf_ptr2char(default_grid.chars[default_grid.line_offset[row]
-                                                  + (unsigned)col]);
-  } else {
-    mouse_char = ' ';
-  }
-
   old_curwin = curwin;
   old_cursor = curwin->w_cursor;
 
@@ -333,6 +324,19 @@ retnomove:
     }
   }
 
+  // Remember the character under the mouse, might be one of foldclose or
+  // foldopen fillchars in the fold column.
+  if (ui_has(kUIMultigrid)) {
+    gp = &curwin->w_grid;
+  }
+  if (row >= 0 && row < Rows && col >= 0 && col <= Columns
+      && gp->chars != NULL) {
+     mouse_char = utf_ptr2char(gp->chars[gp->line_offset[row]
+                                                  + (unsigned)col]);
+  } else {
+    mouse_char = ' ';
+  }
+
   // Check for position outside of the fold column.
   if (curwin->w_p_rl ? col < curwin->w_width_inner - fdc :
       col >= fdc + (cmdwin_type == 0 ? 0 : 1)) {