PtWindow doesn't resize

QNX 6.3 Momentics Pro – Building full-screen GUI. Base window has toolbars at top, right, bottom edges. The remaining area is a workspace in which all subsequent windows will be placed as a result of pressing buttons in the toolbars. That is, callback windows realized in the workspace are all the same size with a variety of different children widgets in each.

The goal is to work in a 1024x768 default environment but react in a well-behaved manner if the graphics should be 1280x1024. (We may have two configurations deployed in the field.)

While testing in both modes, the base window and toolbars look good: the resize flags and anchor settings must be nearly correct. But pressing one of the buttons with a “workspace window” callback produces a correctly-sized window only for 1024x768. In the 1280 mode, it appears to be the same dimensions as for 1024.

I’ve checked flags: managed flags Ph_WM_RESIZE, and _MAX are set. Resize flags: _Y_INITIAL, and _X_INITIAL are set. (I think “INITIAL” is proper because when the windows are first built, they should be sized for the graphics setting which won’t change while running.

I’ve started working on an explicit software solution but so far have not had success. The “set target device” calls return a single device with unit number 5. However, PgGetVideoMode() seems to fail so “get video info” calls don’t get executed.

This may be a big description for a small problem but it’s no less a mystery. Tips? Hints?