Quick and easy way to insert reversible crossfades

The majority of video editors offer some quick and easy way to insert a crossfade transition between all clip fragments.

In Shotcut, it is required to manually overlap clips.
If I want to undo the operation, the overlap behaves as a new clip and clips that I tried to overlap loose their overlapped portions and have to be restored to proper length.
I like how crossfading works in Power Director where I can select all clips in a timeline and automatically insert a standard transition of a preset length.
(Usually crossfade is the default choice and I can live without other options.)

Sometimes long crossfades are useful, yet I would only do it so often.

Is there a way to quickly insert easily reversible crossfades of a standard duration between all clips on a timeline in Shotcut.

Otherwise I really like shotcut.

There is a way to insert selected clips from the Playlist onto the timeline with a specified transition between each. Put the clips in the Playlist, and arrange them in the order you want them to go onto the timeline. Select the clips you want to be combined in this way, and click on the little icon on the right at the bottom of the playlist (the icon looks like three horizontal bars stacked up):

When the context menu pops up, select “Add Selected to Slideshow.” You will see the following dialogue:

Obviously, the “default” purpose of this function is to generate a slideshow from a series of still images, with each images showing for seconds while gradually zooming by amount. But it works just fine with video clips instead of still pictures. You will want to set the Clip duration to a large number, larger than your largest video clip, and turn off the zoom effect by setting it to 0. Set your transition duration and type as desired, and click OK. Voila! Each of the selected clips is transferred to the timeline, with the selected transition applied.

What this will not do is make the transitions easily reversible. I agree that it would be nice to have a quick way to do that, and at first that was a major bother … but once I have gotten used to how Shotcut works, that no longer seems to be a big deal to me.

What if I am gluing together fragments of the same big video file, cutting out parts I don’t want?
How would crossfade transition through the playlist menu help me in this case?

Yes, simply add each sub clip from the Source player to the playlist.

The operation is very inconvenient and is not as easily reversable as in other software like Sony Vegas or powerdirector.
Perhaps I will have to use PowerDirector until you change your mind.