Hi James,
I believe the greyed out/disabled check box is how it's supposed to be. Certainly, that's how it is for all my windows of type Main! using PB 10.5, and it's how it always has been for as long as I can remember.
From PB help for the TitleBar property -
If the window type is a main or MDI frame window with or without MicroHelp, the TitleBar property is always enabled.
So the checkbox forces this property to be enabled and doesn't allow change. Is your disabled TitleBar checkbox checked?
The Title property not taking effect is harder to explain. I'd look for things like code in ancestor windows setting the title, maybe search your pbls for ':0' to see if that text is being set anywhere.
Good luck,
Nathan