STEPS TO REPRODUCE 1. Run KDevelop. 2. Trigger main menu=>Settings=>Configure Toolbars... 3. Right-click on the empty space to the right of the main menu and check a checkbox to show a hidden toolbar, e.g. Debugger Toolbar. 4. Right-click on the empty space to the right of the main menu and uncheck a checkbox to hide a visible toolbar, e.g. Code Browser toolbar. 5. Make a change in the Configure Toolbars dialog, e.g. append the action About KDE to "Main Toolbar <kdevelop>". 6. Click one of the buttons Apply or OK in the Configure Toolbars dialog. OBSERVED RESULT The change made in the Configure Toolbars dialog is applied correctly. The newly visible toolbar becomes hidden again. The newly hidden toolbar becomes visible again. EXPECTED RESULT The change made in the Configure Toolbars dialog is applied correctly. No unrelated toolbar visibility changes occur. SOFTWARE/OS VERSIONS Desktop environment: Xfce KDE Frameworks Version: 6.18.0 Qt Version: 6.9.2 ADDITIONAL INFORMATION https://invent.kde.org/frameworks/kxmlgui/-/merge_requests/270 fixes the bug in KXmlGui, but is stuck in review with no feedback whatsoever for 8 months.