Created attachment 19340 [details]
When Querying for a search, Packagekit currently use a box with a looking glass on top of it. Regularly apps use the spinner in these situation (process-working from the theme) Banshee, Nautilus and Epiphany comes to mind. Possibly the cancellation of the query could be done in the same area as the spinner, so the Find-button next to the search box don't have to change it's name (but perhaps become grayed out instead).
It also seems it's popping up a icon in the notification area, no idea why.
Nahh, I like the search box icon. :-)
With regard to the icon in the notification area, sure, it's a bug it shows momentarily. It's designed to be able to be clickable if the task takes a long time to cancel it, but for a quick search it's not required.
This bug report is very old and based on a version not supported anymore. By upgrading to a newer version of PackageKit you could receive bug fixes and new functionality. You may need to upgrade your Linux distribution to obtain a newer version of PackageKit.