Rectangle Select drop-down box interference with operating system Print Screen button action

[grofaty]

Pinta 1.6 daily PPA on Ubuntu 14.04.

Test 1:
1. Open Pinta and press Print Screen button. One second later Save Screenshot operating system window appears. Print Screen works fine.
2. Close down this window from step 1.

Test 2:
1. Open Pinta and click on Rectangle Select.
2. Click on Selection Mode drop down list and do not select anything just wait.
3. Press Print Screen button and nothing happens - I expect to get operating system Save Screenshot appeared, but it does not. Also if I click ALT+TAB key to switch application during drop-down list is displayed it also does not happen anything. It looks like that drop-down list interference with operating system wide keyboard shortcuts.