Display an overlay showing "generating TSV files, please wait"

[chahuistle]

With the user experience "optimizing" (see c8e7664), we have a new situation: the links for the TSV files will be displayed, but will be disabled.

I think adding an overlay or a progress bar or some sort of visual indication for the user would be a good idea.

[sven1103]

This should be also part of portal-utils-lib, as all portlets should give the same UI experience.

[wow-such-code]

the progress indicator itself should be no problem, vaadin does have multiple options. placement and update depend on each each use case, though. unless we would write some kind of wrapper?

[sven1103]

I think it would be great, if the loading/spinning icon expands automatically to the size of its parent element. That would also fit in the planned view component modularization, we want to do for portal 2.0. An additional function could be an overlay. Just brainstorming here.