Comment 1 for bug 1001773

You can "un-slice" without having an "un-slicing" functionality.

Slicing does not actually slice. It duplicates the clip and tells OpenShot to end the first slice wherever you sliced and begin the second slice at that same point.
A full clip will start at 0 and end at its full length, a cropped clip will start at a value above 0 and/or end at a value below its full length, 2 clips generated by slicing will be as 2 cropped clips with the "begin" value of the second slice identical as the "end" value of the first slice (plus the duration of 1 frame, I guess).

You can full around the start and end of a clip in 2 ways:
- using the "resize" tool
- using the clip properties (duration tab) , and setting the start and end parameters at the desired values

To "un-slice" a clip, you have to look at the start and end value of each slice (properties > duration). Say that slice1 has begin1 and end1 as duration parameters, and slice2 has begin2 and end2 as duration parameters. You eliminate either slice1 or slice2, and set the duration parameters of the remaining slice at begin1 and end2. This will restore your original clip.