arni2033 Reporter
	Description • 8 years ago

>>>   My Info:   Win7_64, Nightly 48, 32bit, ID 20160326030430
STR:
0. Open new tab, open devtools -> Inspector
1. Open http://www.rp-online.de/ in a new selected tab. If your PC is fast, repeat Step 1 ten times.
2. Once you see some content on the page, open devtools (F12)
 [you can accidentally run into bug 1249119]

AR:  Breadcrumbs first appear at the top of markup, then twitch to the bottom
ER:  Breadcrumbs should appear at the bottom (or at the top) but don't twitch - that's for sure.

This additional twitching was introduced in bug 1256422. (Feel free to remove "regression" keyword)

Screencast:
> https://dl.dropboxusercontent.com/s/np6s1phwxd9349r/screencast%201%20-%20%28twitching%20at%20startup%29%20Breadcrumbs%20%2B%20Box%20model.webm?dl=0

	Patrick Brosset <:pbro>
	Comment 1 • 8 years ago

I can reproduce this by making Firefox slow (by opening a lot of tabs as said in step 1), and opening devtools while that happens.

	arni2033 Reporter
	Comment 2 • 8 years ago

STR_2 (very similar):
 1. Open http://www.rp-online.de/ , wait until it's loaded
 2. Open inspector, wait until it's loaded
 3. Press Ctrl+R
AR:  Breadcrumbs first appear at the top of markup, then twitch to the bottom
ER:  Breadcrumbs shouldn't twitch

	arni2033 Reporter
	Comment 3 • 8 years ago

In fact, breadcrumbs first appear at the bottom (1) then teleport to the top, then to the bottom again

You can check statement (1) by setting breakpoint at line  `this._initMarkup();`  (line 201 currently)
in script:   `resource://devtools/client/inspector/inspector-panel.js`   using browser toolbox.

	Joe Walker [:jwalker]
	Comment 4 • 8 years ago

This bug has a priority set that is not P1, so it's not an urgent fix.

	Julian Descottes [:jdescottes]
	Comment 5 • 8 years ago

Adding STRs from arni2033 Bug 1327434

STR_1:
0.(unnecessary) Open 10 tabs with http://www.rp-online.de/ if you can't reproduce
1. Open inspector, open sidebar in inspector, close devtools (F12)
2. Open devtools (F12)

AR:  When inspector launches, sidebar isn't open yet; it appears after several ms (100 - 1000ms)
ER:  When inspector launches, sidebar should be already visible to prevent visual twitching and to
     prevent me from clicking in a wrong place (Note 1) if sidebar appears 0.1s before mouse click.

Notes:
1) Sometimes everything lags, especially if debugger is already opened when I open inspector
   In such cases, I have enough time (1s) to click in the search field in inspector, but instead
   I often hit tabs in sidebar or even buttons in devtools (the latter happens because notification
   "debugger is working, so some functions are disabled" appears. That is a separate issue OFC.)