diff --git a/src/nvim/mouse.c b/src/nvim/mouse.c
index c599f4ea97..c4fa269851 100644
--- a/src/nvim/mouse.c
+++ b/src/nvim/mouse.c
@@ -228,10 +228,6 @@ retnomove:
       redraw_curbuf_later(INVERTED);            // delete the inversion
     }
 
-
-    row -= curwin->w_winrow;
-    col -= curwin->w_wincol;
-
     // When clicking beyond the end of the window, scroll the screen.
     // Scroll by however many rows outside the window we are.
     if (row < 0) {
diff --git a/test/functional/ui/multigrid_spec.lua b/test/functional/ui/multigrid_spec.lua
index 03cb43a7d1..fdf8e66e4f 100644
--- a/test/functional/ui/multigrid_spec.lua
+++ b/test/functional/ui/multigrid_spec.lua
@@ -34,6 +34,7 @@ describe('ext_multigrid', function()
       [17] = {background = Screen.colors.LightGrey, underline = true, bold = true, foreground = Screen.colors.Magenta},
       [18] = {bold = true, foreground = Screen.colors.Magenta},
       [19] = {foreground = Screen.colors.Brown},
+      [20] = {background = Screen.colors.LightGrey},
     })
   end)
 
@@ -2034,6 +2035,66 @@ describe('ext_multigrid', function()
     ]]}
   end)
 
+  it('supports mouse drag with mouse=a', function()
+    command('set mouse=a')
+    command('vsplit')
+    command('wincmd l')
+    command('split')
+    command('enew')
+    feed('ifoo\nbar<esc>')
+
+    meths.input_mouse('left', 'press', '', 5, 0, 0)
+    poke_eventloop()
+    meths.input_mouse('left', 'drag', '', 5, 1, 2)
+
+    screen:expect{grid=[[
+    ## grid 1
+      [4:--------------------------]{12:│}[5:--------------------------]|
+      [4:--------------------------]{12:│}[5:--------------------------]|
+      [4:--------------------------]{12:│}[5:--------------------------]|
+      [4:--------------------------]{12:│}[5:--------------------------]|
+      [4:--------------------------]{12:│}[5:--------------------------]|
+      [4:--------------------------]{12:│}[5:--------------------------]|
+      [4:--------------------------]{12:│}{11:[No Name] [+]             }|
+      [4:--------------------------]{12:│}[2:--------------------------]|
+      [4:--------------------------]{12:│}[2:--------------------------]|
+      [4:--------------------------]{12:│}[2:--------------------------]|
+      [4:--------------------------]{12:│}[2:--------------------------]|
+      [4:--------------------------]{12:│}[2:--------------------------]|
+      {12:[No Name]                  [No Name]                 }|
+      [3:-----------------------------------------------------]|
+    ## grid 2
+                                |
+      {1:~                         }|
+      {1:~                         }|
+      {1:~                         }|
+      {1:~                         }|
+    ## grid 3
+      {7:-- VISUAL --}                                         |
+    ## grid 4
+                                |
+      {1:~                         }|
+      {1:~                         }|
+      {1:~                         }|
+      {1:~                         }|
+      {1:~                         }|
+      {1:~                         }|
+      {1:~                         }|
+      {1:~                         }|
+      {1:~                         }|
+      {1:~                         }|
+      {1:~                         }|
+    ## grid 5
+      {20:foo}                       |
+      {20:ba}^r                       |
+      {1:~                         }|
+      {1:~                         }|
+      {1:~                         }|
+      {1:~                         }|
+    ]]}
+
+  end)
+
   it('has viewport information', function()
     screen:try_resize(48, 8)
     screen:expect{grid=[[