A frequently-asked branding question is how to customize the “gear” page shown during an SPLongOperation. The short answer is “you can’t”; but that’s not entirely true. The operation can be slightly customized using its
As a quick proof of concept, here’s the source of an .aspx you can place in LAYOUTS to see a long operation page that uses the current theme:
I use a
StringBuilder because embedded scripts don’t play well with multi-line constants. In production, I would probably embed the script as a resource.
Here’s the result with the built-in Granite theme: