Select button does not show up after the "Pick Parent Class" window loses focus

If the "Pick Parent Class" window loses focus, the select button will not be available for the previously selected option

1. Open the editor
2. Right click the content browser
3. Click the "Blueprint Class" option
4. Click the drop down for the All classes option
5. Type 'a' into the search field
6. Click "ActorMacros"
7. Alt+Tab back to the editor
8. Try and click "ActorMacros" again
9. Notice that the select button no longer shows up

Expected: The select button would be available when selecting an option from the all classes drop down
Result: If the "Pick Parent Class" window loses focus, the select button will not be available for the previously selected option

New blueprint: Pick parent class dialog