Read-only text field getting unwanted focus

I have a bitmap button with a specific bitmap when it has the focus. It has a child that is a read-only text field, yet it is still getting the focus to him, thus my button bitmap reverts to the normal state.

I'm guessing it shouldn't get any focus since it is read-only, so nothing should change with my button. I searched around the engine looking for the code that got the focus, but I'm still too lost at TGE to find my way out of this one.

Thanks