core: qt layout ui: ux/ui: fixes #26048 keep workbench selector visible

src/Gui/WorkbenchSelector.cpp

@@ -440,4 +440,22 @@ void WorkbenchTabWidget::adjustSize()
     parentWidget()->adjustSize();
 }
 
+void WorkbenchComboBox::setVisible(bool visible)
+{
+    if (!visible && parentWidget() && parentWidget()->isVisible()) {
+        // ignore attempts to hide while parent is visible
+        // this works around a layout bug when toolbar grip is attached
+        // in the menu bar area
+        QTimer::singleShot(0, this, [this]() {
+            if (auto toolbar = parentWidget()) {
+                if (auto areaWidget = toolbar->parentWidget()) {
+                    areaWidget->adjustSize();
+                }
+            }
+        });
+        return;
+    }
+    QComboBox::setVisible(visible);
+}
+
 #include "moc_WorkbenchSelector.cpp"

src/Gui/WorkbenchSelector.h

@@ -53,6 +53,7 @@ Q_OBJECT  // NOLINT
     ~WorkbenchComboBox() override = default;
     WorkbenchComboBox(WorkbenchComboBox&& rhs) = delete;
     void showPopup() override;
+    void setVisible(bool visible) override;
 
     WorkbenchComboBox operator=(WorkbenchComboBox&& rhs) = delete;