Hi Friends, This is coming from a report on Inkscape Community forum:
https://forum.inkscapecommunity.com/index.php?topic=567.0
Even though the member marked it fixed, I'm not sure the fix was really an appropriate fix.
Short version
The user couldn't get the Ruler LPE to work properly. In the topic, you can see screenshots from the user's file and also when I tested using their file. Their SVG file is also attached, in case someone wants to test. But here's link for convenience:
https://forum.inkscapecommunity.com/index.php?action=dlattach;topic=567.0;at...
The user was able to make the LPE function properly by changing the Scale factor to 1.0. However, I suspect that will result in some other unwanted change (either a different page size than is set, or a DPI different from 96....or something?).
At first, I was confused, and I thought there might be a problem with the scale factor, because I thought a new doc should start with scale factor = 1.0. But now the user reports that it did originally start with mm units and scale factor 1.0. When they changed to px, Inkscape correctly changed the scale factor.
So now, I think that points to the LPE not liking the unit change very much.
Could someone who understands this better than me, have a look at that please? Does there need to be a bug report?
Thank you very much, brynn