MUI_PAGE_COMPONENTS: User should at least check 1 of 2 optional sections

Hi,
I've got a MUI_PAGE_COMPONENTS.
There are 3 sections:
Section "!RequiredComponents" SectionMain
Section "OptionalData1" OptionalData1
Section "OptionalData2" OptionalData2

The user should at least select one of the two optional sections.

But how do I control this (which sections are selected?) and send him back to the MUI_PAGE_COMPONENTS, if none is selected?

Should I implement something like
!define MUI_PAGE_CUSTOMFUNCTION_POST "checkSectionSelection"
!insertmacro MUI_PAGE_COMPONENTS

Thanks for tips, Gérôme

there are several threads about this on the forum already, search around. Also, sections.nsh has some handy macros

The problem was: what to search for?

But finally I found:


This helped me to solve my problem.

Thx, Gérôme