SUMMARY

When taking screenshots of a rectangular region with Spectacle, the image is offset by a fair bit, and as a result there are some regions that I can't include in the screenshot.

This appears to be caused by a mixture of increasing monitor scaling factor (Settings > displays) and font DPI (settings > fonts > force fonts DPI).

The change seems to be irreversible (resetting scaling factor and font DPI to the values from before scaling factor was increased doesn't make the issue go away). 

This doesn't appear to be a Spectacle bug, as I've noticed similar behaviour in kcolorchooser as well. 



STEPS TO REPRODUCE
0. 'Force fonts DPI' should be checked. Value doesn't matter. Scaling factor should be set to 1. 
1. Go to Settings > display, change scaling factor
2. Go to Settings > Fonts, change 'Force fonts DPI' to a different value
3. (Optionally) reset scaling factor back to 1 and 'Force fonts DPI' to original value.



OBSERVED RESULT

When selecting rectangular region for the screenshot with Spectacle, everything is offset to the left. KColorChooser picks color that's offset from the cursor, but in the opposite direction than Spectacle.

EXPECTED RESULT

When selecting rectangular region for the screenshot, windows don't get offset. Kcolorchooser picks color under the cursor, not somewhere way off.

SOFTWARE/OS VERSIONS
Linux: 4.19.8-2-MANJARO 
KDE Plasma Version: 5.14.4
KDE Frameworks Version: 5.52.0
Qt Version: 5.11.2

ADDITIONAL INFORMATION

I will provide screenshots as a separate attachments.