Sections and subsections

[Fretje]

Hello,
I want to achieve something simple, but I don't get it to work like I want to.
I have 2 sections "section1" and "section2". Section2 can not be installed without section1.
So I thought I make them displayed in the components page like the attached picture.

I have done this using the following code:

SectionGroup /e "Section1" SEC1Group
Section "-Section1" SEC1
...
SectionEnd
Section "Section2" SEC2
...
SectionEnd
SectionGroupEnd

This way I thought the behaviour I described above will be automatically implemented, because I thought when a section of a particular sectiongroup is selected, the sectiongroup itself is also selected. But this seems not to be the fact.
When the group is de-selected first, both checkboxes are de-selected, then afterwards the "section2" section can be checked, and the section1 checkbox gets grey (like a 3-state checkbox in the 3rd state). I want it to be checked plain (all the subgroups are checked, so the group should be checked).

Then I thought I override the .OnSelChange as follows:

Function .onSelChange
!insertmacro SectionFlagIsSet ${SEC2} ${SF_SELECTED} endOnSelChange selectSection1
selectSection1:
!insertmacro SelectSection ${SEC1}
endOnSelChange:
FunctionEnd

But this makes it unable to de-select group1.

Am I missing something here? Or is there another way of doing this?

Any help appreciated!

Greetings,

Fretje