> 1) I can't figure out how to rename the class of an existing object in the SCX. There doesn't seem to be a rename option (or anything that looks like it would do the trick) available anywhere that I can see.
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> 2) The object in question doesn't show up anyway, because the class browser doesn't seem to be showing all objects on the form. The object I need to "fix" is a combobox that is contained in a tabbed page on the form and none of those objects (not even the tabbed page container object) shows up in the class browser.
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>Am I doing something wrong or are there limitations to messing with a SCX in this manner?
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No limitations. When you bring up the form in the class browser, you will see the name of the SCX and the name of the form in the left pane. Click on the form and the form objects will show up in the right pane. Click on the object (in the right pane) that you want to modify. Then click on the second toolbar button (tooltip = redefine) on the right. You're done!