Dolphin F3 button(double panel mode)

I’ve been fought for that for then make disable double panel mode, then only inactive panel left as one. Why? It’s weird. Is this a bug?

I think it work as intended at least for me. Pressing F3 opens up the split folderview. And pressing F3 again closes the active folderview.

Is there chance for change it? Really annoying thing

There is no configuration option for it. You can only try editing the source code.