Fix committed to master branch: http://bugs.limesurvey.org/plugin.php?page=Source/view&id=19483

No more table transformation applies when screen is under 801px (for a few exotic tablet screens, see 11016), whereas visible-xs-block respect bootstrap standards (767px). If too many bugs of this kind appears in the future, we should just refuse to support weird exotic tablet screens. We should repsect standards, we should not try to fit to non standards devices.

https://bugs.limesurvey.org/view.php?id=11016

Many thanks for the very fast response!!!!
Can you tell me in which new build number this issue is fixed??? So I can tell the IT to upload this new version

Thanks again!!!!

well it will in next release, probably next monday.
If you want to patch it by your self, it's pretty easy, just tell to your IT to add those lines at the end of the file "template.css" of your template :

@media only screen and (max-width: 801px) {
.visible-xs-block{
display: block !important;
}
}

I will do that, thanks again!

Version 2.50 Build 160620 released