QGIS » QGIS Application

Playing around a little more with it,starting with a new project...
1. Add two layers
2. Add group layer
3. Move the two layers to the group layer.
4. With all three activated, add Theme.
5. Add another layer; move it out of the group if necessary.
6. Turn off group layer.
7. Click on Theme to activate.
7r. Group layer does not activate. Theme shows active.
8. Turn on group layer to reveal layers.
8r. Theme shows inactive.
9. Turn off layers inside group.
9r. THEME SHOWS ACTIVE?!
10. With the sublayers already off, turn off group layer.
10r. Theme still shows active!

Do I understand that correctly that the issue is that if the layers in a theme are within a group the group must be switched on if at least one of the layers is visible?

Let's make an example V=visible v=visible-grey:

[V] Group 1
    [V] Layer 1
    [V] Layer 2
-> save theme
-> make some changes in the tree
[ ] Group 1
    [v] Layer 1
    [ ] Layer 2
-> activate theme
[V] Group 1
    [V] Layer 1
    [V] Layer 2
-> make some changes in the tree
[V] Group 1
    [V] Layer 1
    [ ] Layer 2
-> activate theme
[V] Group 1
    [V] Layer 1
    [V] Layer 2

If this is the issue, a patch is coming ...

Note that group status is not saved in the themes.

The group layers have always responded to the the toggling of any of its sublayers. THAT may actually be the bigger issue here. So yeah, I think you got it then. I didn't realize that the problem isn't with the Themes, but with how the groups and sublayers are responding to each other. Thanks!