933967 - Theme previews intermittent

Status: RESOLVED INCOMPLETE

(addons.mozilla.org Graveyard :: Public Pages, defect)

Description

[Amy Tsay [:amyt]]

We're getting reports that either nothing happens when you mouse over a theme, or there is a delay, or you have to move the mouse on and off the theme to get it to preview.

It is being discussed here: https://forums.mozilla.org/addons/viewtopic.php?f=30&t=15112

The scenario I can reproduce is this:

1) Go to https://addons.mozilla.org/en-US/firefox/themes/?sort=created
2) Mouse over a theme
3) The header shows a preview of the background color, but not the image
4) Move the mouse to another area of the same theme
5) The image now shows in the header

Expected behavior is that you would see the header the first time you hover over a theme, without having to move your mouse again.

Comment 1

[Christopher Van Wiemeersch [:cvan]]

AFAICT this has been an issue for years. From my assessments, it seems to depend on the size of the theme images. Firefox likely doesn't prefetch these images, so the preview is not going to be instant; waiting a while with your mouse hovered over the theme preview will eventually make the theme show up. There may be a Firefox bug on file we can dupe this to. CC'ing MattN, knowledge of all things Theme-related.