Ok so I worked out the first one. An errant message being sent "deep" to descendants caused the mysterious lockup and it's specific to any tab controls not just the tab view. Solved that by fixing the message. Incidentally any information on generating guaranteed unique timerId's within an app? I'm OK with unique messages and GUID but the ID of the timer is poorly documented.

Point 2 still stands, change the line in the sample app and the tabs don't render.

Two issues,

1. When resizing an XTTabView all is OK until the size reduces to the point where the <> arrows need to be drawn at this point the dialog window (when undocked obviously) jumps back to the initial size of the window and all toolbars, menus become unresponsive. The application window also refuses to move but all else functions OK. I noticed this symptom is mentioned in very old release notes relating to TabCtrlBars. Is this a known problem. For the record the tab view is not using XP style so doesn't use any of the OnDrawTop/left/right etc routines in the source.

2. When I add ModifyTabStyle(NULL,TCS_MULTILINE) the problem above goes away. However, the tabs do not render. I tried this in the codejock sample app - TabView - in exactly the place where the sample code has a commented out line for putting tabs at the bottom. The same thing happens, half the tabs are not rendered at all.

Any input would be good as otherwise I'll have to bin out the TabView which would be a shame.