Please describe the problem:
It is possible to fool the logic to display the memory registers window

Steps to reproduce:
1. Load gcalctool
2. Check view->memory registers. The memory register window opens and the
menu item is checked.
3. Close memory register window using window manager controls. Window closes
and menu item is unchecked.
4. Check view->memory registers. Window does not open. Menu item is checked.
5. Check view->memory registers. Window opens. Menu item is unchecked.
From now on, the logic is inverted until you go back to step 3

Actual results:


Expected results:


Does this happen every time?
Yes

Other information: