Opening menu and reloading .desktop files results in ghost menu, hanging, and crashing

If you right-click a Docklike icon (opening a menu), then reload the .desktop files with the menu open, the menu disappears into an outline, and Docklike hangs until you right-click the rest of the panel.

• Run sleep 2; konsole or similar. For some reason, opening (or closing?) Konsole (installed from KDE, not Xfce) triggers g_signal_connect(G_OBJECT(mMonitor), "changed", ...).
• Right-click an icon.

Half a second after Konsole appears, the menu disappears but the outline remains. Docklike hangs until you right-click another part of the panel.