I wanted a slider control in a modeless dialog that had a variable number
of tick marks. As this does not seem to be a variable parameter I am using
DisposeControl() and CreateNewControl() from a set of control resources
with different scale markings, changed by a keystroke.

All that works fine, with live updating too, but after a number of changes
the slider suddenly stops working i.e. it cannot be moved with the mouse
anymore. It is drawn enabled, its position can be changed via
SetControlValue(), but it cannot be grabbed. After a certain number of
changes, one new control will work again. The number of changes is not a
constant and varies with each run. The first created slider always remains
working, sometimes the next one is dead, sometimes I might be able to
change it several times, but I always get a dud eventually.

What would cause this behaviour?
Shouldn't this be taken care of entirely by DialogSelect()?