Fix disabling of groups (#709)

[RainCT]

This was broken with commit 5897285, which reverted the changes from
commit c6dacb1, but rather than only removing the change concerning
the read-only attribute, commented out the entire check, including
the parent_->getDisableChildren() call (which existed prior to
commit 5897285).

[wjwwood]

@dgossow can you comment on this?

[RainCT]

Any update on this?

[wjwwood]

I'm not willing to merge this until I get positive feedback from @dgossow or @hersh, or until I look into myself. I don't have time right now, but I'll try to squeeze in some time this afternoon, but since this is touching code recently changed by @dgossow I was hoping he could just glance at it and give it a 👍 or 👎.

[hersh]

I'm looking at this now...

[hersh]

I just tested rviz with and without this change. I see the need for it, as the current hydro-devel version does not disable the children of a DisplayGroup when you disable the group. Makes the groups feature pretty lame.

This change fixes that and doesn't seem to hurt the Views list behavior, so I'm giving this a +1.

+1.

[wjwwood]

Sounds good to me.

[wjwwood]

I'll make sure to have a reasonable soak time for the next release of rviz.

[efernandez]

@wjwwood Could this be backported to hydro-devel?

[wjwwood]

#769