#17 Toolbar editing buttons are not disabled in read-only mode

[Kimmo Varis]

When a file edit is switched to read-only mode, toolbar buttons that edit file content aren't disabled. This confuses user as the buttons just don't do nothing when clicked.

Affected buttons are:
- Cut
- Paste
- Replace

[Nobody/Anonymous]

It seems it is a more general problem.
Compared to Edit menu items sensitivity :
- No file open : Cut, Copy, Paste, Find, Replace are not disabled
- Cursor on __ (end of file) : Cut, Copy are not disabled