Fix iterator invalidation in panel_manager::deserialize()

[neitsa]

Summary

SUMMARY: Bugfixes "Fix iterator invalidation in panel_manager::deserialize()."

Purpose of change

Discovered while debugging a Debug build which crashed in panel_manager::deserialize(); pannels.cpp

The crash didn't show up in the release build but looking at the debugger on the Debug build it was clearly coming from the debug allocator on it->toggle where the pointer validation was wrong (honestly it took me some time to understand what was the problem...).

                if( it2->get_name() == name ) {
                    if( it->get_name() != name ) {
                        window_panel panel = *it2;
                        layout.erase( it2 );
                        layout.insert( it, panel );
                    }
                    it->toggle = joPanel.get_bool( "toggle" ); // crash here!

It happens that erase() and insert() invalidate iterators and all elements after the iterator, as per the C++ reference.

Describe the solution

Simply set the current iterator as the one returned by layout.insert():

                    if( it->get_name() != name ) {
                        window_panel panel = *it2;
                        layout.erase( it2 );
                        it = layout.insert( it, panel ); // get the iterator here
                    }
                    it->toggle = joPanel.get_bool( "toggle" ); // no crash

Describe alternatives you've considered

N/A.

Additional context

After this fix and a rebuild, the code doesn't trigger a crash and the panels seems to be working as intended.

[ifreund]

Thank you, that one was my bad.