[205_2009] Fix inconsistent document rendering when closing tabs

devel/205_2009.md

@@ -0,0 +1,23 @@
+# 205_2009 Fix inconsistent document rendering when closing tabs
+
+## Problem
+Issue #2009: When using "Documents in separate windows" mode with Tab bar enabled, closing a tab causes the remaining document's rendering to become inconsistent (different font rendering for the same content).
+
+## Root Cause
+In `kill_window()` (`src/Texmacs/Data/new_window.cpp`), when the last tab in a window is closed, `set_current_view()` is called to switch to the surviving window's view. However, `set_current_view()` only updates the view pointer — it does not call `resume()` on the editor. Without `resume()`, `notify_change(THE_FOCUS + THE_EXTENTS)` is never triggered, so the font environment and layout are not recalculated, resulting in inconsistent rendering.
+
+## Fix
+Added `resume()` and `send_keyboard_focus()` calls after `set_current_view()` in `kill_window()`. This follows the same pattern used by `var_focus_on_buffer()` in `new_view.cpp`, ensuring the rendering pipeline is properly triggered when switching to the surviving window.
+
+## Steps to Reproduce
+1. Open Mogan
+2. Set Edit > Preferences > Buffer management > Documents in separate windows
+3. Set View > Tab bar
+4. Type Chinese text (e.g., `集合与映射`)
+5. Set Font to Microsoft YaHei, size 14pt
+6. Create a new document
+7. Close the new document in Tab bar
+8. Observe: the original document's rendering has changed
+
+## Files Changed
+- `src/Texmacs/Data/new_window.cpp`: Added `resume()` and `send_keyboard_focus()` in `kill_window()`

src/Texmacs/Data/new_window.cpp

@@ -350,7 +350,15 @@ kill_window (url wname) {
     url win= view_to_window (vs[i]);
     if (!is_none (win) && win != wname) {
       set_current_view (vs[i]);
-      // FIXME: make sure that win obtains the focus of the GUI too
+      // Ensure the editor is properly resumed so that rendering
+      // state (fonts, zoom, extents) is recalculated correctly
+      {
+        tm_view vw= concrete_view (vs[i]);
+        if (vw != NULL && vw->ed != NULL) {
+          vw->ed->resume ();
+          send_keyboard_focus (vw->ed);
+        }
+      }
       delete_window (wname);
       return;
     }