486551 - GTK native widgets ignore <meta http-equiv="msthemecompatible" value="no">

Status: RESOLVED DUPLICATE of bug 966240

(Core :: Widget: Gtk, defect)

Description

[Zack Weinberg (:zwol)]

It's supposed to be possible to turn off native form controls for the entire document by putting <meta http-equiv="msthemecompatible" value="no"> in the HEAD.  Or anyway we support that on Mac and Windows.  But nsNativeThemeGTK doesn't check for it so on Linux the tag has no effect.  This tripped me up testing the patch for bug 475535 (which regressed bug 373381, but I didn't see it because the tests use the above tag).

I'm a little dubious about whether we should support this at all, nowadays (it appears to be an IE6 compatibility hack), but given that we do it oughta be cross platform.  And the flag in the pres shell that the tag sets might someday get set by other stuff too (I can see a hidden pref to disable native themes being useful if only for testing).  Attached patch does this; I'm assuming that there is no problem with rendering any non-native widget on Linux given that for a long time it didn't *do* native controls.

Comment 1

[Zack Weinberg (:zwol)]

Attachment: patch

Comment 2

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Seems worth adding a reftest for this (comparing it to -moz-appearance:none).

I think we implemented support for this pretty recently, actually.

Comment 3

[Zack Weinberg (:zwol)]

Problem with writing a reftest is, -moz-appearance:none doesn't work on <input type="file"> and makes <select> look ever so slightly different than it does with the meta tag.  I suppose both of those are also bugs ...

Comment 4

[philippe (part-time)]

meta http-equiv="msthemecompatible" value="no" has been supported (Win/Mac) for a while, with many issues.
Bug 247161 on Windows, sorta fixed I think.
Bug 420363 on Mac, fixed by disabling 'msthemecompatible' for scroll bars, and bug 464876 for a 'better' fix.

I always wondered why this non-standard meta tag ought to supported. Neither Opera, nor WebKit Safari support it.
See also bug 322218.

Comment 5

[(not currently active) Ted Mielczarek]

I was looking for a bug about removing support for this tag. The code appears to be fairly old. The blame in CVS goes back to 2003 where it was refactored into the file it's in now. Seems like a pretty silly thing to support these days. It makes my page scrollbar non-themed, which is weird.

Comment 6

[Zack Weinberg (:zwol)]

(In reply to comment #5)
> I was looking for a bug about removing support for this tag. The code appears
> to be fairly old. The blame in CVS goes back to 2003 where it was refactored
> into the file it's in now. Seems like a pretty silly thing to support these
> days.

I would support dropping it (cross-platform), FWIW.  I can do an alternative patch to that effect.

> It makes my page scrollbar non-themed, which is weird.

That sounds like a bug - it should not affect chrome.  (Maybe the page scrollbar is being treated as content?)