If a Business System contains more than (approximately) 330 Procedures, then, when opening the Dialog Design with this Business System selected, a popup appears
"The dialog design is unable to display approximately 2 objects".
If the procedure that cannot be displayed is a batch procedure, then it is not possible to add a procedure step.
If two client procedures cannot be displayed, then it is not possible to link them with a flow.
It is also not possible (in order to move some procedures to another business system) to "Copy with Substitution" an undisplayed procedure.
In order to make the above three actions possible, i suggest that the Dialog Design window should have a feature "View/Filter..." (just like there is a View/Search... and View/Neighbors") that would allow to display only those procedures starting with or containing a given string.