Bug 211994

Summary: MobileSafari falsely claims CSS resize property support
Product: WebKit Reporter: Bramus <bramus>
Component: CSSAssignee: Nobody <webkit-unassigned>
Status: NEW ---    
Severity: Normal CC: koivisto, mjs, simon.fraser, tomac, webkit-bug-importer, wenson_hsieh, zalan
Priority: P2 Keywords: InRadar
Version: WebKit Nightly Build   
Hardware: Unspecified   
OS: iOS 13   
See Also: https://bugs.webkit.org/show_bug.cgi?id=210473

Description Bramus 2020-05-17 03:08:21 PDT
Recently I wrote an article on using CSS `resize: both;`: https://www.bram.us/2020/05/15/css-only-resizable-elements/

In browsers that don't support this property I wanted to show a warning on screen to notify users thereof. For this I use an @supports rule:

.warning {
    display: block;

/* Hide warning in case browser supports resize: both; */
@supports (resize: both) {
    .warning {
        display: none;

I've come to notice that MobileSafari – which does not support `resize: both;` – hides the warning and thus falsely claims to support said CSS resize property.

Demo: https://codepen.io/bramus/pen/RwWeqOP
Comment 1 Radar WebKit Bug Importer 2020-05-18 03:48:02 PDT