Rafi -
It appears that the LoadCallback causes the OI to be non-responsive. We can look into that. What I recommend is the following.
Create a tool menu sequence open the target sequence file, send a message to the OI to create a window for the target sequence file, and then release the target sequence file.
If you want to run a sequence in the target sequence file, you can just call the sequence using a sequence call step.
See attached sequence files.
Scott Richardson (NI)
Scott Richardson
https://testeract.com