Hello Joel,
Let me explain in brief how the RadFormDecorator decorates dropdownlists. It positions the real dropdown outside the visible viewport (e.g sets left to be -99999) in order to hide it and puts the skinned element instead on the palace of the original dropdown. However, the skinned dropdown gets another ID which is formed by the original ID and the prefix "Skinned" because the original dropdown should keep the original ID in order to handle the events. The scenario with the tooltip is a specific one because you need to set the tooltip the ID of the hovered element to show it. Since in IE and FF the speed of decorating, initializing, etc is different you get the different result. We are aware of this problem and it will be soon fixed. For the time being, I suggest to set the skinned ID along with isClientID - this should fix the problem under all browsers:
As to the RadInput controls, there was a similar problem there because the clientID of the element which should be tooltipified is different than the server ID. However, this problem is fixed and it should work out of the box. In case you continue experiencing problems with integration of RadToolTip and RadInput, please send me some relevant code and I will do my best to help.
All the best,
Svetlina
the Telerik team