ThemeBuilder administration errors in Internet Explorer

As I evaluate ThemeBuilder for use within our company, we're really won over by the flexibility the tool offers. However a number of issues are being identified with it working happily with Internet Explorer. My version is 6 (6.0.2900.2180.xpsp_sp2_gdr.070227-2254CO), and I've conducted testing with all add-ons disabled.

This set of issues occurs in the Administration interface for ThemeBuilder. The attached Word document contains screen captures to illustrate the issues.

1. Clicking on the Manage Spaces tab loses the tab strip. Need to click on Theme Administration in the ThemeBuilder group of menu options in order to get it back.

2. Second issue occurs with "Default Layouts". If I go to the Dashboard tab first it works fine, but if I choose Theme Administration and then go straight to Default Layouts I get a Javascript error.

3. If the Dashboard tab displays correctly and I choose to Restore the window position (or Maximize it) then the contents of the web page re-adjust to fit and the tab strip is lost once more.