Description:
Lately (not sure only lately), I have been seeing row numbers on the left be black boxes.  If I force refresh, e.g. "Insert new row", all the ones below that redraw correctly. Scrolling off and back on does not fix.

I see black boxes over the numbers / letters.  Should be black numbers on grey background, but I was getting back boxes on grey background, completely covering the number/letter.  Sometimes just 2 couple in a row, sometimes 50 in a row.  But always contiguous.

Steps to Reproduce:
1. Open a spreadsheet
2. Scroll up and down a few times randomly
3. Some row numbers are blacked out

Actual Results:
It happened.  I even opened a smaller spreadsheet with only a small number of used cells and it happened.  Actually, then I opened a new spreadsheet and there were immediately blacked out row numbers AND column letters...
I also notice I only need to click on a cell (like N8) and then the N and the 8 redraw correctly.

Disabling OpenGL does not fix.  But it appeared there were less back boxes. Causally related? Not sure.

Switched back and now I can no longer duplicate.  I was going to attach a screen shot, but no longer can I guess.  

Expected Results:
Numbers / letters to show normally


Reproducible: Sometimes


User Profile Reset: Yes


OpenGL enabled: Yes

Additional Info:
[Information automatically included from LibreOffice]
Locale: en-US
Module: SpreadsheetDocument
[Information guessed from browser]
OS: Windows (All)
OS is 64bit: no

Copied and pasted:

Version: 6.2.8.2 (x64)
Build ID: f82ddfca21ebc1e222a662a32b25c0c9d20169ee
CPU threads: 8; OS: Windows 6.1; UI render: default; VCL: win; 
Locale: en-US (en_US); UI-Language: en-US
Calc: threaded