IE7 Conversion Question

I'm updating my app for IE7, and finding a series of formatting "anomalies" that seem to be related to "WIDTH" and "HEIGHT" of panels and Gridviews and DetailViews.   Most of the situations that I've run into so far seem to involve a Panel that's set up with vertical scrollbars, and a Gridview or DetailView inside it;  the purpose is to scroll the Control  inside the panel, and not scroll the entire page.  

IE6 seemed to be much more forgiving if the Panel didn't have a height or width, or if the height was less than the text content of the Panel (if it only had text), or the Panel width was less than the width of the Control.

IE7 seems (at least in my initial attempts) to be inconsistent (but I'll bet it's not!) in allowing some Panel/Control combinations to not have Panel Width, and come out fine, and not working in other cases (the Panel, with no Width, is too narrow for the control).

My questions are:
a)  Is this behavior that other people have encountered in updating their app's to IE7, and
b)  Are there any general guidelines to use to work with this?

Any guidance on this would be appreciated.

Thanks!