1238390 - Transition from forward button to no forward button creates weird transition and twitching in Urlbar

Status: RESOLVED INVALID

(Firefox :: Theme, defect)

Description

[arni2033]

Attachment: screenshot 1 - identity block and url twitching.png

>>>   My Info:   Win7_64, Nightly 46, 32bit, ID 20160107030235
STR:
1. Open "about:about" in a new tab
2. Select all text in urlbar, type "about:" instead of selected text, press Enter
3. Click Back button in navigation toolbar
4. Hover mouse over Forward button in navigation toolbar, left-click it
5. Move mouse away from Forward button

Result (see comment 2):       
 After Step 3 padding-left of identity block is immediately decreased (screenshot 1),
   and only after that forward button starts sliding to the right.
 After Step 5 padding-left of identity block is immediately increased (screenshot 2),
   and only after that forward button starts sliding to the left.
 Subconscious of the user is completely destroyed by extra twitching
  (isn't there enough twitching already?)

Expectations: 
 No extra twitching. Actually, I already told in bug 1231025 that all design is very twitchy and
 distracting. So I hope that 1231025 will be fixed by (in particular) always showgin forward button
 In this case, this bug will not be actual.

Comment 1

[arni2033]

Attachment: screenshot 2 - identity block and url twitching.png

Comment 2

[arni2033]

Attachment: testcase 1 - click on page to see twitching of identity block and url.html

Here's the testcase I made to demonstrate current behavior. Click on page to show/hide forward buttons
"Better" and "Fine_too" are my vision of how that transition could work (without twitching)

If this testcase isn't clear enough - please request screencasts and detailed explanation

Comment 3

[:Gijs (he/him)]

We no longer hide the forward button.