V20.9.903 and V20.9.904
Test with a logfile (for this test it have to be at least lines for several pages, my testfiles has ~10000 and more than 300000 lines)
test 1:
in Customize Markers \ Marker List
1. one Marker from the list is enabled
2. open the file (logfile)
-> the Marker is highlighted (it’s ok)
3. disable this Marker in Customize Markers \ Marker List (no one is enabled)
-> the Marker is still highlighted (it’s not ok)
4. scroll down ~ one page
-> after this visible page there is nothing highlighted in subsequent lines ()
5. scroll up back to the line what i saw by begin
-> the Marker is still highlighted the page where i saw on begin ()
6. scroll down several pages
7. scroll up to first page
-> nothing highlighted (it’s ok)

A comparable behavior i get when no markers are disabled and I enable it. On the visible page no highlighted Markers, sroll several pages down and up again to the first page, all Markers highlighted. I looks like the enable/disable of Markers works only on lines where not visible at moment by make this change (cache/buffer problem).
The same behavior I have with “Auto Marker” (a very helpful function is for me). Nothing highlighted on visible page, only by scroll up/down several pages.
test 2:
1. open a file (in my case logfile with more the 10000 lines)
2. sroll down (in my case line 1000)
3. select a word (option “retrieve word at cursor” is not enabled)
4. sroll up
-> selected word is highlighted from line ~ 765 to line 1
5. scroll down
-> now selected word is highlighted from line ~982 to end of file
6. sroll down to line ~ 1300
-> now selected word is highlighted from top to end of file (it’s ok)
7. sroll to line 1000, select a other word
-> new word is not highlighted on this page, first seleted word is still highlighted
8. swroll down
-> old selected word is highlighted up to line 1039, after line ~ 1040 the new word is highlighted

For the tested tests, more or less side changes were necessary to see this behavior
With smal files (only some lines, less than one page) “Auto Marker” not working at all (scrolling up and down not posible).

I test it also whit disable and enable “use directwrite”.