in inkscape (0.92 and 1.0) if a file has many objects:
1. "copy & insert" / select lines < 1sec 2. "copy & insert" / select lines with enpdoint (e.g. arrow) 3-15sec
It does not matter if inserting 1 new item or 20 at a time ... both take up to 15sec (I mention this just for clarity of the effect - cloning is not the point here).
It is the same behavior on a laptop i5 as on a high performance desktop i7 under windows.
Any idea how to speed up working or is this a bug?