Testing Joomla 4 Beta 7 and Helix Ultimate Alpha 4 template. Installed SP Page Builder Pro 3.7.9

I created an SPPB Page, using one of the template/page layouts included in SPPB Pro. The page previews OK. When trying to create a menu item, it won't let me select the specific SPPB page once I have selected the "Menu Item Type". The Modal window I would expect to open and list the SP PB pages does not open.

I can create normal menu item (Single Article) to a Joomla article, so it doesn't appear it is the "create menu item" function in J4B7 that is the problem; I just can't select a SPPB page once I have selected create menu item (SP Page Builder type).

I don't know if this is an issue with J4, Helix Ultimate or SP Page Builder. I have not had this issue with SPPB 3.7.9 in Joomla 3.9.24 using the current stable Helix Ultimate template (v1.1.2)

Thanks.