>>One of the crucial things in my solution was calling a minimal function inside each app/exe, IIRC setting classlib for the unique classlibs found inside that package. I think Stack was along the lines of:
>>

>>GO.exe
>>   .... with setting classlibs there
>>
>>      do startHH.prg in HH.app
>>          do tapdance.prg in Multirisk.App with tcCall, tcApp &&& necessary: set Multirisk Classlibs from inside, call real starter 
>>             Do (tcCall) in (tcApp) {a startprogram included in HH.app)
>>

>>With this structure the multirisk classlibs are added inside a function of Multirisk.app AND Multirisk.App is kept on stack while code of HH.App does its work.
>
>In my case it's a set of loose files in a subfolder - a vcx, few prg-based classes, all based on the parent classes inside the exe. And now the funny part - the sequence of events:
>
>- the current form in the main exe has a container with a grid, which is coming from the subfolder\addon.vcx
>- the grid has a column with tiny pictures (not .ico, .png, for which I had to use pictureval, otherwise they couldn't find the .png files inside the exe)
>- doubleclick a row on the grid launches the form, with parameters taken from current row. Before launching the form I set classlib to ... in my.exe (without paths, will try with paths today)
>- the form is a class in subfolder\addon.vcx (previously it was a .scx, and everything worked while the .scx was inside the exe, and it instantiated all it needed to from subfolder\addon.vcx), with a few containers and subcontainers from subfolder\addon.vcx, all based on classes which exist in the exe
>- it bangs when creating one of those containers from subfolder\addon.vcx, the message is "classlib (parent of container) not found"; before that it readily creates a few objects based directly on classes from main exe

First tries from me would be:

1) trying to start next form via not included Prg instead of directly from subfolder\addon.vcx aggregated on Exe form (easy to check, but only 9% estimate of succeding)
2) trying to start next form via included Prg instead of directly from subfolder\addon.vcx aggregated on Exe form (easy to check, but only 15% estimate of succeding)
3) In exe, instantiate a class ONLY in subfolder\addon.vcx as property on screen, start second form from method of that class (harder to check, only 7% estimate of succeding but I'd do before 4)
4) stimulate brain by repeated forehead/keyboard connections