For running J!5.1 you must https://fabrikar.com/forums/index.php?wiki/update-from-github/ or include the new file manually https://fabrikar.com/forums/index.php?threads/joomla-5-1-and-fabrik-cannot-find-files-error.54473/post-285151 See also Announcements
Please see our announcement here.
.plupload_container {
width: 100% !important;
min-height: auto !important;
}
should there not be a Save button ? I can only see a "Close" butto