Double Commander is good, indeed, but has some rough edges.
DC uses some components that are made by different authors and that are not that flexible and users ask for features which are beyond what those components can offer. So this is a dead end since nobody is updating/adapting the components so the features could be implemented.
DC has only two listed active developers, one of which is the author and the other one is new and fixes mostly Mac problems. If someone knows Free Pascal and Lazarus IDE or is interested in contributing, it would be to the benefit of all the users. I imagine it is not a trivial task to keep this program running on Windows/Linux/Mac with only two people.
For Windows, Unreal Commander is also good. Also Free Commander, but it is the slowest of all the orthodox file managers.