>>> My Info: Win7_64, Nightly 49, 32bit, ID 20160526082509 STR_1: 1. Hover mouse over any non-empty folder in bookmarks panel 2. Hover mouse over the 1st item in that folder AR: The 1st item's button is placed lower than the folder's button ER: The folder's button and the 1st item's button should be aligned correctly: they should have the same vertical coordinate. Reference of good behavior: bookmark items in bookmarks toolbar STR_2: (detailed) 0. Create folder "asdf1" in bookmarks toolbar. Create subfolder "asdf2" in "asdf1". Create subfolder "asdf3" in "asdf2". Create subfolder "asdf4" in "asdf3". Create subfolder "asdf5" in "asdf4". 1.A) Click "asdf1" on bookmarks toolbar, then hover "asdf2" > "asdf3" > "asdf4" > "asdf5" 1.B) Open bookmarks panel, hover "Bookmarks toolbar" > "asdf1" > "asdf2" > "asdf3" > "asdf4" > "asdf5" AR: A) Popups opened in Step 1 create a staircase: each next button is placed lower than the previous one B) Popups opened in Step 1 are all aligned on the same horizontal line. No staircase (good) ER: Scenario (A): there should be no staircase, just like in scenario (B). Popups should be aligned well

User Agent Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:53.0) Gecko/20100101 Firefox/53.0 Build ID 20170116030326 I was unable to reproduce this issue on Nightly 49 (BuildID 20160526082533), on the latest Firefox release (50.1.0) or the latest Nightly (53.0a1). The actual results that are described are the other way around, sub-menus opened in the Bookmarks toolbar are opened in a horizontal line and the ones in the Bookmarks Sidebar and Library (Ctrl+Shift+B) are aligned in a staircase. I have tested this on two different machines, one with Windows 10 and the other with Windows 7. Based on the fact that the reporter's account is disabled I will mark this as Resolved - Incomplete. If anyone can still reproduce it on latest versions, feel free to reopen the issue and provide more information.