Weird OptionButton behavior

[Troy Reagan]

Hi,
I have a pair of option buttons in a frame, within another frame on a Vb6 form. There are several other controls on the form in their own frames or directly on the form. What I have observed is that after the option buttons are disabled and then re-enabled, based on a combo box selection, tabbing through changes which option is selected. If I continue to tab or shift-tab after the value is changed, it leaves the current selection and tabs through the currently selected control as expected. When tabbing through before changing the value in the combo box it tabs through as expected. We have a very similar dialog which doesn't display this behavior. I have done a code comparison on it and can't find any reason why this is occurring. Note: In the one that is having weird behavior, the form is being loaded in a VB.NET form vs. the other is loaded by either another VB6 form or a C# form (I have confirmed this isn't the cause, I loaded the other VB6 form from the VB.NET form and it still doesn't exhibit the behavior). Any help with this would be appreciated.
Troy