About selecting/deleting many components at the same time, you can already do that. You select the first component of the list that you want to select, and you select the last one while holding the shift key. It will select everything between the first and the last items selected. --- Added: Not true anymore. See below.
That's what I do when a layout is finished to save a second version of the layout with only the cut tracks and the jumpers on it. It makes it easier to locate the tracks to cut and tp add thejumpers.
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Now, I had a strange problem after submiting the layout to your site Bancika. When I try to exit the program, it gives me an error, as you can see in the picture. It opens a window signaling the error, and I can't close that window, or exit the program anymore.

And it seems to do that only after submiting a layout.

But the rest of the program works better than before.
Added: I kept working with the program again this evening, and I realised that we can't select many components at the same time anymore

I will miss that option...
Gilles