1483714 - Unnecessary scroll bar in drop-down when <select> has background style

Status: NEW

(Core :: Layout: Form Controls, defect, P3)

Description

[ce]

Attachment: screen-shot.png

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:62.0) Gecko/20100101 Firefox/62.0
Build ID: 20180802174131

Steps to reproduce:

When a <select> has a background style applied, the drop-down menu that appears when clicking it has an unecessary scroll bar, at least on Firefox 62 on macOS.

(The fact that background styles on the <select> element itself affect the drop-down menu at all is very irritating, tbh. Though pretty much everything about <select> is, i guess.)

See attached screen-shot and test case.


Actual results:

When the <select> has a background style specified in CSS, the associated drop-down menu has an unnecessary vertical scroll bar (which only scrolls by a pixel or two in either direction).


Expected results:

The drop-down menu should only have a scroll bar when it's too big for the view port or it exceeds the maximum number of menu items (which is 20, i think).

Comment 1

[ce]

Attachment: test case.html

Comment 2

[Stefan [:StefanG_QA]]

Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:62.0) Gecko/20100101 Firefox/62.0 20180817100105

I have tested this report on Windows and OS X 10.12 using latest Nightly, Beta and Release build. I was able to reproduce the mentioned behavior when loading the attached test case in comment 1. When the drop-down is shown an unnecessary vertical drop-down is displayed. Actually, the scrollbar can be moved only with 1 or 2px.