zingo:
When I enter a nonexistent file into the “Mercurial Executable” field, (such as foobar.exe), at first nothing happens. When I switch to the next field, the “apply” and “ok” buttons are grayed out (because the form has errors). Only when I switch back to the executable field does the “Value must be an existing file” error message appear in the title, but if the form page loses focus (or I switch to the username field), the message diesappears again.
Handling these error messages doesn’t seem to be consistent through all of eclipse, but it seems that the errors should be displayed regardless of focus (as a reference, see how General/Editors/Text Editors behaves with multiple errors), and that validation should occur immediately on change (and not after the field has lost focus).
this is a copy of http://www.assembla.com/spaces/mercurialeclipse/tickets/174