Fix a regression that caused clicking in the padding/margins of windo…

…ws in the stack layout to switch the window to the first window

Fixes #2604

docs/changelog.rst

@@ -14,6 +14,9 @@ To update |kitty|, :doc:`follow the instructions <binary>`.
 - By default, double clicking no longer considers the : as part of words, see
   :opt:`select_by_word_characters` (:iss:`2602`)
 
+- Fix a regression that caused clicking in the padding/margins of windows in
+  the stack layout to switch the window to the first window (:iss:`2604`)
+
 
 0.17.3 [2020-04-23]
 --------------------

kitty/mouse.c

@@ -514,7 +514,8 @@ window_for_event(unsigned int *window_idx, bool *in_tab_bar) {
         Tab *t = global_state.callback_os_window->tabs + global_state.callback_os_window->active_tab;
         for (unsigned int i = 0; i < t->num_windows; i++) {
             if (contains_mouse(t->windows + i) && t->windows[i].render_data.screen) {
-                *window_idx = i; return t->windows + i;
+                *window_idx = i;
+                return t->windows + i;
             }
         }
     }
@@ -529,8 +530,10 @@ closest_window_for_event(unsigned int *window_idx) {
         Tab *t = global_state.callback_os_window->tabs + global_state.callback_os_window->active_tab;
         for (unsigned int i = 0; i < t->num_windows; i++) {
             Window *w = t->windows + i;
-            double d = distance_to_window(w);
-            if (d < closest_distance) { ans = w; closest_distance = d; *window_idx = i; }
+            if (w->visible) {
+                double d = distance_to_window(w);
+                if (d < closest_distance) { ans = w; closest_distance = d; *window_idx = i; }
+            }
         }
     }
     return ans;