Is it possible to create an Action Text entry in Merge Module project (like MSI project) for the custom actions in order to display a text while the custom is being executed?
I think you can, but it takes some tinkering. In the merge module project, you'll need to add the ActionText table in the Direct Editor view (either export from another project and import into the MSM project, or manually create the table with Action, Description, and Template columns of types s72, L64, and L128).
In the new ActionText table, put this into the Action column---
ActionName.HHHHHHHH_HHHH_HHHH_etc.
---where ActionName is the action name in the Custom Actions view, and HHHHHHHH_etc. is the Module ID GUID value from the General Information view.
The Description column takes the text you want to display: "Now running merge module action..."
After adding the merge module to your installer project, the action's text should appear at the usual time. Normal conditions apply: must be deferred action, etc.
