Gui: fix regression: show commands of selected category in Toolbar tab

src/Gui/DlgKeyboardImp.h

@@ -85,8 +85,6 @@ public:
                            AccelLineEdit *currentShortcut = nullptr);
 
 protected:
-    void showEvent(QShowEvent* e) override;
-
     /** @name Internal helper function for handling command list widgets
      */
     //@{
@@ -115,6 +113,7 @@ protected Q_SLOTS:
     void onModifyMacroAction(const QByteArray&) override;
 
 protected:
+    void showEvent(QShowEvent* e) override;
     void changeEvent(QEvent *e) override;
     void setShortcutOfCurrentAction(const QString&);
 

src/Gui/DlgToolbarsImp.cpp

@@ -782,6 +782,17 @@ void DlgCustomToolbarsImp::moveDownCustomCommand(const QString& name, const QByt
     }
 }
 
+void DlgCustomToolbarsImp::showEvent(QShowEvent* event)
+{
+    Q_UNUSED(event);
+    // If we did this already in the constructor we wouldn't get the vertical scrollbar if needed.
+    // The problem was noticed with Qt 4.1.4 but may arise with any later version.
+    if (firstShow) {
+        ui->categoryBox->activated(ui->categoryBox->currentIndex());
+        firstShow = false;
+    }
+}
+
 void DlgCustomToolbarsImp::changeEvent(QEvent *e)
 {
     DlgCustomToolbars::changeEvent(e);

src/Gui/DlgToolbarsImp.h

@@ -102,6 +102,7 @@ public:
     ~DlgCustomToolbarsImp() override;
 
 protected:
+    void showEvent(QShowEvent* e) override;
     void changeEvent(QEvent *e) override;
     void addCustomToolbar(const QString&) override;
     void removeCustomToolbar(const QString&) override;
@@ -114,6 +115,7 @@ protected:
 private:
     QList<QAction*> getActionGroup(QAction*);
     void setActionGroup(QAction*, const QList<QAction*>& group);
+    bool firstShow = true;
 };
 
 /** This class implements the creation of user defined toolbox bars.