We added "ps-gxt" to the RootPanel, and added ".ps-gxt" to all reset stuff, for example: .ps-gxt div
The problem is, by doing so the order for which the styles are applied is changed. For example, for a grid header element:
Using firebug, the two screenshots show the difference. Notice the padding in the second picture (our stylesheet) overwrites .x-grid3-hd-inner, causing the header to appear incorrectly shorter.
<div id="x-auto-11" class=" x-grid3-hd-inner x-grid3-hd-title x-component" style="width: 392px; height: 14px;">...</div>
The fix is to apply .ps-gxt to .x-grid3-hd-inner. Probably need to apply to entire gxt-all.css, which is a nightmare when upgrading GXT.
Is there a better way?