Installation/uninstalation type "Full", but not exactly

Hi!
I have the following problem. My installer installs some components, selected by the customer (via the corresponding component dialog). By uninstallation is checked which components are really installed and the sections for the not installed ones are unchecked and made read only. So nothing new here. Now it comes my problem. I allow "Custom" and "Full" uninstallation. On "Custom" uninstallation all works well. But when I select "Full" uninstallation, the not installed components are also checked (they still stay read only). So my question is if it is possible somehow to forbid changing of read-only section when the installation type is changed or how to recognize if the installation type is changed and to update again the state of the sections?

I found that the .onSelChange is called not only by clicking on the sections, but also when the installation type is changed. So this is a possible solution for me.