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The rendering engine often fails to draw pages correctly.

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Text pages are often littered with black bars that obscure the lettering, almost like redaction. Refreshing the page usually solves the issue. Also, the bookmarks bar will often present with a pattern of dark gray and light gray blocks, which resolves when the mouse cursor passes over them. The attached images show what I mean.

Text pages are often littered with black bars that obscure the lettering, almost like redaction. Refreshing the page usually solves the issue. Also, the bookmarks bar will often present with a pattern of dark gray and light gray blocks, which resolves when the mouse cursor passes over them. The attached images show what I mean.
Attached screenshots

All Replies (2)

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Start Firefox in Safe Mode {web Link} by holding down the <Shift>
(Mac=Options)
key, and then starting Firefox. A small dialog should appear. Click Start In Safe Mode (not Refresh).

Is the problem still there?

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Thanks, FredMcD. I have not observed the effect since starting in safe mode. I guess, from the disappearance of my add-ons, that this means an add-on is the likely culprit, and that the next step is to introduce them one by one until the issue recurs. I'll try that and see what happens. It might take a day or three to report the results.