Emitted when the user right-clicks the toolbar or uses the
keybinding to display a popup menu.
Application developers should handle this signal if they want
to display a context menu on the toolbar. The context-menu should
appear at the coordinates given by @x and @y. The mouse button
number is given by the @button parameter. If the menu was popped
up using the keybaord, @button is -1.
Emitted when the user right-clicks the toolbar or uses the keybinding to display a popup menu.
Application developers should handle this signal if they want to display a context menu on the toolbar. The context-menu should appear at the coordinates given by @x and @y. The mouse button number is given by the @button parameter. If the menu was popped up using the keybaord, @button is -1.