CSS property · data last changed 10 Nov 2026
[popover] in email clients
Works in 3 of 21. Not supported in Gmail, Gmail Android, Gmail iOS and 12 more. Partial in Samsung Mail and Thunderbird. Untested in Superhuman.
Your reader in Outlook Classic sees the email without [popover], even if it looks right where you tested it.
caniemail (MIT) via @emailens/engine 0.18.22
What to do instead in Outlook Classic
There is no drop-in fix for [popover] in Outlook Classic. Design so the email still reads without it.
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[popover] is not among the 24 features we have screenshotted on real installs. The ones we have →
All 21 clients, problems first
| Client | Support |
|---|---|
| Gmail | Not supported |
| Gmail Android | Not supported |
| Gmail iOS | Not supported |
| Outlook 365 | Not supported |
| Outlook (New) | Not supported |
| Outlook Classic | Not supported |
| Outlook iOS | Not supported |
| Outlook Android | Not supported |
| Outlook for Mac | Not supported |
| Yahoo Mail | Not supported |
| Yahoo Mail Android | Not supported |
| Yahoo Mail iOS | Not supported |
| HEY Mail | Not supported |
| AOL Mail | Not supported |
| Fastmail | Not supported |
| Samsung Mail | Partial See caveat 1 |
| Thunderbird | Partial See caveat 2 |
| Superhuman | Untested |
| Apple Mail | Works |
| Apple Mail iOS | Works |
| Proton Mail | Works See caveat 3 |
Caveats (3)
- 1. Samsung Mail: Partial. Not supported with Hotmail/Outlook accounts.
- 2. Thunderbird: Buggy. A button with just an image inside will trigger an image zoom rather than the popover.
- 3. Proton Mail: Partial. Does not work with command/commandfor attributes only with popovertarget/popovertargetaction
Caveats as recorded by caniemail (MIT), one entry per wording.
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