Installation view and program view

Hi all,

 i have a timer schedule to update ui and use DataModel to store the changes values in InstallationNodeContribution,   and the method runs well in installation view and could see the values changes;
 And in ProgramNodeContribution, i use api.getInstallationNode and want to get the changes value continuously。
but found that the value in program ui changes only when i change to “installation”tab ,  if just stop in “Program” tab, the value will not changes.
so is the timer schedule  only runs when is in “installation” tab view model?