fix: right-click in clickable statusline #19252

Problem:
1. Right-click does not work in statusline unless you left-click first (to focus
   the statusline).
2. Modifier (e.g. shift+rightclick) does not work in statusline.

Solution:
Make clickable statusline sections receive right-clicks regardless of whether
the statusline is focused.

Closes #18994

1 files changed, 68 insertions, 34 deletions

diff --git a/src/nvim/mouse.c b/src/nvim/mouse.c
index 2ea108d3df..a4a521fa80 100644
--- a/src/nvim/mouse.c
+++ b/src/nvim/mouse.c
@@ -128,8 +128,10 @@ bool is_mouse_key(int c)
 /// @param which_button  MOUSE_LEFT, MOUSE_RIGHT, MOUSE_MIDDLE
 int jump_to_mouse(int flags, bool *inclusive, int which_button)
 {
-  static int on_status_line = 0;        // #lines below bottom of window
-  static int on_sep_line = 0;           // on separator right of window
+  static int status_line_offset = 0;        // #lines offset from status line
+  static int sep_line_offset = 0;           // #cols offset from sep line
+  static bool on_status_line = false;
+  static bool on_sep_line = false;
   static bool on_winbar = false;
   static int prev_row = -1;
   static int prev_col = -1;
@@ -144,6 +146,7 @@ int jump_to_mouse(int flags, bool *inclusive, int which_button)
   int col = mouse_col;
   int grid = mouse_grid;
   int fdc = 0;
+  bool keep_focus = flags & MOUSE_FOCUS;
 
   mouse_past_bottom = false;
   mouse_past_eol = false;
@@ -164,10 +167,10 @@ int jump_to_mouse(int flags, bool *inclusive, int which_button)
 retnomove:
     // before moving the cursor for a left click which is NOT in a status
     // line, stop Visual mode
-    if (on_status_line) {
+    if (status_line_offset) {
       return IN_STATUS_LINE;
     }
-    if (on_sep_line) {
+    if (sep_line_offset) {
       return IN_SEP_LINE;
     }
     if (on_winbar) {
@@ -189,49 +192,78 @@ retnomove:
   old_curwin = curwin;
   old_cursor = curwin->w_cursor;
 
-  if (!(flags & MOUSE_FOCUS)) {
-    if (row < 0 || col < 0) {                   // check if it makes sense
-      return IN_UNKNOWN;
+  if (row < 0 || col < 0) {                   // check if it makes sense
+    return IN_UNKNOWN;
+  }
+
+  // find the window where the row is in
+  wp = mouse_find_win(&grid, &row, &col);
+  if (wp == NULL) {
+    return IN_UNKNOWN;
+  }
+
+  on_status_line = (grid == DEFAULT_GRID_HANDLE && row + wp->w_winbar_height >= wp->w_height)
+    ? row + wp->w_winbar_height - wp->w_height + 1 == 1
+    : false;
+
+  on_winbar = (row == -1)
+    ? wp->w_winbar_height != 0
+    : false;
+
+  on_sep_line = grid == DEFAULT_GRID_HANDLE && col >= wp->w_width
+    ? col - wp->w_width + 1 == 1
+    : false;
+
+  // The rightmost character of the status line might be a vertical
+  // separator character if there is no connecting window to the right.
+  if (on_status_line && on_sep_line) {
+    if (stl_connected(wp)) {
+      on_sep_line = false;
+    } else {
+      on_status_line = false;
     }
+  }
 
-    // find the window where the row is in
-    wp = mouse_find_win(&grid, &row, &col);
-    if (wp == NULL) {
-      return IN_UNKNOWN;
+  if (keep_focus) {
+    // If we can't change focus, set the value of row, col and grid back to absolute values
+    // since the values relative to the window are only used when keep_focus is false
+    row = mouse_row;
+    col = mouse_col;
+    grid = mouse_grid;
+  }
+
+  if (!keep_focus) {
+    if (on_winbar) {
+      return IN_OTHER_WIN | MOUSE_WINBAR;
     }
+
     fdc = win_fdccol_count(wp);
     dragwin = NULL;
 
-    if (row == -1) {
-      on_winbar = wp->w_winbar_height != 0;
-      return IN_OTHER_WIN | (on_winbar ? MOUSE_WINBAR : 0);
-    }
-    on_winbar = false;
-
     // winpos and height may change in win_enter()!
     if (grid == DEFAULT_GRID_HANDLE && row + wp->w_winbar_height >= wp->w_height) {
       // In (or below) status line
-      on_status_line = row + wp->w_winbar_height - wp->w_height + 1;
+      status_line_offset = row + wp->w_winbar_height - wp->w_height + 1;
       dragwin = wp;
     } else {
-      on_status_line = 0;
+      status_line_offset = 0;
     }
 
     if (grid == DEFAULT_GRID_HANDLE && col >= wp->w_width) {
       // In separator line
-      on_sep_line = col - wp->w_width + 1;
+      sep_line_offset = col - wp->w_width + 1;
       dragwin = wp;
     } else {
-      on_sep_line = 0;
+      sep_line_offset = 0;
     }
 
     // The rightmost character of the status line might be a vertical
     // separator character if there is no connecting window to the right.
-    if (on_status_line && on_sep_line) {
+    if (status_line_offset && sep_line_offset) {
       if (stl_connected(wp)) {
-        on_sep_line = 0;
+        sep_line_offset = 0;
       } else {
-        on_status_line = 0;
+        status_line_offset = 0;
       }
     }
 
@@ -239,8 +271,8 @@ retnomove:
     // click, stop Visual mode.
     if (VIsual_active
         && (wp->w_buffer != curwin->w_buffer
-            || (!on_status_line
-                && !on_sep_line
+            || (!status_line_offset
+                && !sep_line_offset
                 && (wp->w_p_rl
                     ? col < wp->w_width_inner - fdc
                     : col >= fdc + (cmdwin_type == 0 && wp == curwin ? 0 : 1))
@@ -251,7 +283,7 @@ retnomove:
     if (cmdwin_type != 0 && wp != curwin) {
       // A click outside the command-line window: Use modeless
       // selection if possible.  Allow dragging the status lines.
-      on_sep_line = 0;
+      sep_line_offset = 0;
       row = 0;
       col += wp->w_wincol;
       wp = curwin;
@@ -266,7 +298,7 @@ retnomove:
     if (curwin != old_curwin) {
       set_mouse_topline(curwin);
     }
-    if (on_status_line) {                       // In (or below) status line
+    if (status_line_offset) {                       // In (or below) status line
       // Don't use start_arrow() if we're in the same window
       if (curwin == old_curwin) {
         return IN_STATUS_LINE;
@@ -274,7 +306,7 @@ retnomove:
         return IN_STATUS_LINE | CURSOR_MOVED;
       }
     }
-    if (on_sep_line) {                          // In (or below) status line
+    if (sep_line_offset) {                          // In (or below) status line
       // Don't use start_arrow() if we're in the same window
       if (curwin == old_curwin) {
         return IN_SEP_LINE;
@@ -284,25 +316,27 @@ retnomove:
     }
 
     curwin->w_cursor.lnum = curwin->w_topline;
-  } else if (on_status_line) {
+  } else if (status_line_offset) {
     if (which_button == MOUSE_LEFT && dragwin != NULL) {
       // Drag the status line
       count = row - dragwin->w_winrow - dragwin->w_height + 1
-              - on_status_line;
+              - status_line_offset;
       win_drag_status_line(dragwin, count);
       did_drag |= count;
     }
     return IN_STATUS_LINE;                      // Cursor didn't move
-  } else if (on_sep_line && which_button == MOUSE_LEFT) {
+  } else if (sep_line_offset && which_button == MOUSE_LEFT) {
     if (dragwin != NULL) {
       // Drag the separator column
       count = col - dragwin->w_wincol - dragwin->w_width + 1
-              - on_sep_line;
+              - sep_line_offset;
       win_drag_vsep_line(dragwin, count);
       did_drag |= count;
     }
     return IN_SEP_LINE;                         // Cursor didn't move
-  } else if (on_winbar) {
+  } else if (on_status_line && which_button == MOUSE_RIGHT) {
+    return IN_STATUS_LINE;
+  } else if (on_winbar && which_button == MOUSE_RIGHT) {
     // After a click on the window bar don't start Visual mode.
     return IN_OTHER_WIN | MOUSE_WINBAR;
   } else {