I had just updated to RC9 (under MacOS 10.3.3) and took my solution for a spin, when out of nowhere a method that displays a list-view form would not work.
I realized that selecting designer from the tool menu, in designer mode, in this list form would keep the form in a “mixed” mode: toolbars greyed out but elements where accessible to be moved and edited.
I traced the problem to a field that had lost definition (no name, no dataprovider); deleted this field and everything back no normal.
Hope this helps.
Ronnie