UDT handler and Optimizer Rules during load

Hello Coresuite Community,

I created a UDT to save a bom for a quotation item line calculation. I use the Customize UDT handler to manage functionality to add, delete or update data on the udt and to open this function by the context menu in sap quotation. I also created optimizer rules as formload, formcompleted and value changed events when the UDT handler was started. The formload and formcompleted events adding tabs, textboxes and buttons to the form and also including the eventhandlers. I had to seperate them because items of the UDT handler form cannot be accessed in formload event. They are available first on the formcompleted event.

My issue is now, that during start of the UDT, first it opens the form with the included table for the udt and after that, my optimzer rules formload and formcompleted events adding the new items to the form. This hole process looks very strange in SAP, because the user see how the form beginns to change in shape. 

I tried to work with form invisible and freeze to keep the form invisible until all items added to the form. But that isn't working neither in formload nor in fromloadcompleted event.

Is their a way to keep the form invisible until all items are added to the form?

Greetings Sebastian