Handle conflicting shortcuts in a nicer way.

[farmaazon]

Follow up of #7527

The proper fix for conflicting shortcuts' problem should be to handle them by focus; The shortcuts in project view should not be global shortcuts, and the shortcuts should be handled "upwards": if the focused element does not handle a given shortcut, his parents should be checked one after another, and global shortcuts only then.

[somebody1234]

I'm assuming this is a non-issue in GUI2 due to bubbling of regular DOM events.