Comment 33 for bug 1491064

I have the same issue with inkscape 1.0beta1 (fe3e306, 2019-09-17) installed via snap on Ubuntu 18.04.
But I noticed something potentially interesting though: for me, the *slowdown only happens when the mouse cursor is inside the inkscape window*.

Steps to reproduce:

1) Load a sufficiently complex file that displays slow text editing.
2) hit F1 (selection tool) and click on a text element
3) move the mouse cursor *outside the inkscape window*
4) hit F8 (text tool) and edit the text element via keyboard only (it's very fast for me)
5) hit F1 again
6) move mouse cursor back into inkscape window

This procedure makes text editing quite fast again. The slowdown is recovered if step 3) is omitted.
Perhaps this can help to point towards the cause, maybe something with updating the mouse cursor style (from arrow to text-cursor) is inadvertantly checking for potential overlap with *all* text elements?

Just my 2 cents. Hope this helps in nailing this bug down. It is a real show-stopper (also using Inkscape for scientific figures and posters)