Context menu actions with no selected Item has no effect

[Blattlaus]

This Bug is similar to #604293 but I think the proposed fix doesn't cover this problem.

'''How to reproduce'''
1) create a new item called "test"
2) right click on an item "test" and delete it (now, no item is selected)
3) right click on another item and choose "Schedule for today"

'''Expected result'''
The item under the pointer gets selected and is marked for today

''Actual result'''
Nothing happens

'''Proposed solution'''
If a right click is detected on the list and no item is selected, select the item under the mouse pointer before processing the event.

[Chris Johnston (cjohnston)]

I think any time you right click, the item under the pointer should be selected. This would make functionality the same as if you just right click on an icon on the desktop, you get a menu for that icon.

[Izidor Matušov (izidor)]

This could be annoying for somebody who uses right-click menu a lot. I think it is because we try to support multiple selection, we somehow forbid selecting by a right click.

[Izidor Matušov (izidor)]

It seems to me that this is fixed into current trunk, marking as "Fix Committed"