Issue with SetGadgetState() and SetGadgetItemState() on Windows

[Fred]

For tree, you need to use #PB_Tree_AlwaysShowSelection, not #PB_ListIcon_AlwaysShowSelection. You can't have a 1:1 display rendering between all the subsystems, but the internal behaviour (is the item selected or not) should be indeed consistent.

[bal]

For tree, you need to use #PB_Tree_AlwaysShowSelection, not #PB_ListIcon_AlwaysShowSelection.

My bad juggling with 3 different gadgets

Thanks for looking into this, Fred.