Affected versions

• Firefox 66.0b13 (20190304101322)
• Firefox 65.0 (20190124174741)
• Firefox 65.0.2 (20190225143501)
• Firefox 67.0a1 (20190305092747)

Affected platforms

• Windows 10 x64
• Ubuntu 16.04 x64
• macOS 10.13.6

Steps to reproduce

1. Open Firefox and go to about:preferences#search.
2. Double click to display keyword input field in the Search engine list view (e.g. Double click "Bing" row).
3. Type keyword and do not press the ENTER key (e.g. "b" not include quotation)
4. Click "General" pane
5. Click "Search" pane
6. Click anywhere on the word typed at Step 3 and start typing again.

Expected result

• The keyword can be edited.

Actual result

• Unable to edit the keyword.

Regression range

• This is not a recent regression as I can reproduce on 65.0 as well. I will investigate further in case of an old regression.

Hello, please see below the pushlog:

Last good revision: 1a5b53a831e5a6c20de1b081c774feb3ff76756c (2016-08-29)
First bad revision: 26e22af660e543ebb69930f082188b69ec756185 (2016-08-30)
Pushlog:
https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=1a5b53a831e5a6c20de1b081c774feb3ff76756c&tochange=26e22af660e543ebb69930f082188b69ec756185

Mike, does anything from the regression-window point to being the cause?

Duping to the bug that has the error messages from the browser console when this happens which made this easy to fix...