Dialog updating issue

[CelticMinstrel]

Sometimes, dialogs do not properly update until they have lost focus and then gained it again. This issue has been around for awhile, and there are some fixes committed, but the bug still shows itself in some contexts. Though passing a parent dialog pointer usually helps in specific cases, I believe there is some deeper issue here that I don't know how to solve.

For the record, some places that I think I recall seeing the issue recently:

• Preferences dialog
• Choose string dialogs invoked from the edit terrain dialog