Right-click menu without an open database

[oscargus]

When right-clicking without an open database, the "tab menu" is opened with all options enabled. More or less every option leads to some sort of exception, typically an NPE since there is no current BasePanel. The best way would be to disable these, with a backup alternative of checking for a null return value of getCurrentBasePanel().

It wasn't straightforward (to me) to disable them as the popup code and the creation are in different files. Passing all actions would be a feasible alternative, but maybe someone is more clever than that.