diff --git a/src/mouse.c b/src/mouse.c
index fe5c14c..f895779 100644
--- a/src/mouse.c
+++ b/src/mouse.c
@@ -172,9 +172,7 @@
     if (mouse_comp_pos(curwin, &row, &col, &mpos->lnum, NULL))
 	return IN_STATUS_LINE; // past bottom
 
-    mpos->col = vcol2col(wp, mpos->lnum, col);
-
-    mpos->coladd = 0;
+    mpos->col = vcol2col(wp, mpos->lnum, col, &mpos->coladd);
     return IN_BUFFER;
 }
 #endif
@@ -3204,7 +3202,7 @@
  * The first column is zero.
  */
     int
-vcol2col(win_T *wp, linenr_T lnum, int vcol)
+vcol2col(win_T *wp, linenr_T lnum, int vcol, colnr_T *coladdp)
 {
     char_u	    *line;
     chartabsize_T   cts;
@@ -3222,6 +3220,8 @@
     }
     clear_chartabsize_arg(&cts);
 
+    if (coladdp != NULL)
+	*coladdp = vcol - cts.cts_vcol;
     return (int)(cts.cts_ptr - line);
 }
 #endif
@@ -3242,6 +3242,7 @@
     varnumber_T wincol = 0;
     linenr_T	lnum = 0;
     varnumber_T column = 0;
+    colnr_T	coladd = 0;
 
     if (rettv_dict_alloc(rettv) == FAIL)
 	return;
@@ -3275,7 +3276,7 @@
 	    if (row >= 0 && row < wp->w_height && col >= 0 && col < wp->w_width)
 	    {
 		(void)mouse_comp_pos(wp, &row, &col, &lnum, NULL);
-		col = vcol2col(wp, lnum, col);
+		col = vcol2col(wp, lnum, col, &coladd);
 		column = col + 1;
 	    }
 	}
@@ -3285,5 +3286,6 @@
     dict_add_number(d, "wincol", wincol);
     dict_add_number(d, "line", (varnumber_T)lnum);
     dict_add_number(d, "column", column);
+    dict_add_number(d, "coladd", coladd);
 }
 #endif