extjs webapp.
we have a complex full screen layout, which has a form. the form has a custom field component which launches a window, the window has additional form fields that need to post, so we parent the window such that he is a descendent of the form panel. when we set modal:true, we get a modal mask over just the panel which the window is owned by (good) but the modal mask is sized wrong, causing inappropriate scroll bars on the form.
if you look at the modal window's mask implementation[1], it's quite clear that modal windows are not intended to mask anything other than the entire page. I usually agree with the Extjs implementation details, which makes me wonder if modal windows in sub-panels have design or usability challenges that I don't forsee?