1327366 - Modal confirm dialog appears many times on about:config, if I hold Enter

Status: NEW

(Core :: XUL, defect)

Description

[arni2033]

>>>   My Info:   Win7_64, Nightly 49, 32bit, ID 20160526082509
STR_1:
1. Open url  "about:config?filter=pixelsper"
2. Click on the pref to select it (the line will become blue)
3. Hold Enter for 5 seconds
4.(bonus) Click on the top modal dialog. Press Escape once. Press Ctrl+T. Type "asdf" in urlbar

AR:
 Step 3 - many modal dialogs appear one above another, causing horrifying box-shadow around them
 Step 4 - top modal dialog closes, and focuses content, so you can freely navigate/type with keyboard

ER:
 Step 3 - no more than 1 modal dialog should appear
 Step 4 - when modal dialog closes, it should focus another modal dialog if it's present

Note:  I added Step 4 just in case somebody would argue that there's no bug in Step 3

Comment 1

[Emil Pasca [:emilpasca]]

User Agent:  Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:53.0) Gecko/20100101 Firefox/53.0

I have tested this issue on Windows 10 x64 with the latest Firefox release (50.1.0) and the latest Nightly (53.0a1-20170103030204) and managed to reproduce it.
When loading the url described in the STR_1, selecting the pref and holding the Enter key for 5 seconds, many modal dialogs appear one above another, causing the box-shadow around them. I was also able to reproduce the issue described in step 4.