as far I understand you try to make programms with caqtdm. That is not the intention behind a display manager. The work of a
displaymanager is to interact with the controls system world. In case of caqtdm this is EPICS. If you want to try to programm with caQtDM you can
use the caqtdm_lib part of caqtdm. Anton Mezger made an example (http://epics.web.psi.ch/software/caqtdm/ [3. Howto]).
caqtdm supports calculations (caCalc) EPICS Calc and Perl Regular Expressions and this for visibility. Qt Signals can also be used for Actions.