I found a semi-serious bug.
If you are using radformdecoration with decoratedcontrols set to "all", any asp textbox that has textmode set to "multiline" will simply disappear in IE7.
I tried a few skins and this was the case with them all.
I'm using a temp solution which is to add this definition to the skin files.
| visibility: visible !Important;
which works fine. But obviously we will need a non-css solution in the long run.