1. It seems that when you use the Wix/ascend form, over a manually coded form, the form container overrides the stack within it. This results in the stack properties becoming unresponsive, so you can't change the height/width values. Any clicks on the stack just re-select the form container.
This is an issue when the stack size becomes larger than the form container, and you can't adjust it. Attempting to access the stack from the layers panel also proves unresponsive. The only fix is to jiggle the properties of the form fields to find which one is linked to the closest edge.
I think a good fix would be to somehow link the stack's edge values to the form container's edge values, or allow the stack to be directly edited.
2. All form fields in the Wix/ascend form seem to have linked sizes. I have been unable to create a form where one field is at 50% width, and another is at 100% width. Changing either field sets the width properties of the other.