Fix field label list and right panel view CSS issues

[Tom-TBT]

I noticed a few issues after the 7.4.0 release.
Maybe the CSS didn't come from that release but I thought they could be included in a patch.

• Field was always suggested as a label even when the image did not come from a plate (because I changed to field instead of the alias wellsample)
• The cross to delete labels sometime wrapped to the next line (changing the window zoom could trigger that)

• same for scalebar pt

I also set scrollbar properties so that when it appears, it doesn't affect the layout of the right panel.