Free open-source alternative to Total Commander

It seems I almost found alternative for [TotalCommander](http://www.ghisler.com/" target="_blank). Let me present [DoubleCommander](http://doublecmd.sourceforge.net/" target="_blank). It is free, open-source, extendible by Total’s plugins. That’s awesome. I also found out that viewer plugin SGView for TotalCommander can be  completely replaced by ImaginePlugin. Imagine has x64 version. The issue was to assign hotkeys like in SGView.