Trim does not work as expected

I have a question about the trim command. In my opinion the trim command is more like extend .. ?? Well .. maybe I am missing something ..  in architecture a common task looks like this .. (for instance door o window openings):



And the result should look like this ..



To do this in librecad .. I have to use divide eight times (!) and then delete the all lines I do not need.  In other cad programs I just select all trim lines, when I am done I press enter and then start trimming all lines I do not want, which is much easier. Is there a better way than divide to do this in librecad ?

The problem for the trim tool is to know where to stop. When trimming Line A with Trim A, the right rest of the line is removed to the end, there will not remain a Line A' to trim with Trim B.

In LibreCAD we have no tool to specify multiple limit entities for trim command.
Thus divide must be used before trimming, but it's enough to us it two times. Then finish with the Trim Two tool.

1) Divide Line A and Line B at the green circles position. This shortens Line A  and Line B and you get two new entities Line A' and Line B' 
2) With the Trim Two tool then trim the 4 edges by clicking at the magenta circles position. The result should match with your expectations.

I think this is the fastest way in LibreCAD.

Armin