In the current toolbar there are two buttons that relate to the "Image navigator" view:

• one button next to the undo/redo buttons is a toggle button, supposed to show/hide the view
• the other button appears among the regular view buttons, cannot be toggled and only shows the view when clicked

Example for inconsistent states:

• start application, make navigator disappear if necessary
• click the right navigator button (the one for the view)
• click the toggle button

now the toggle button is in the "pressed/on" state but the navigator is hidden.

Could be solved by suppressing the navigator in the regular view buttons