Original report: https://bugs.launchpad.net/ubuntu/+source/gedit/+bug/721465

Open gedit.
Open, say four or five files with long filenames in tabs.
Make the window narrow enough so that some file's tabs are not visible.
Use the mouse scroll wheel on the tabs to move between them.

ISSUE: Because
  - gedit's tabs don't show partially, and
  - switching to tab left or tab right is not smoothly animated,
it make it difficult to use the visuo-spatial benefit of tabs to locate the open file you are interested in. If there was smooth scrolling (animated, rather than abrupt) and allowed partial (visually clipped) tab display, I would not "overscroll" past the desired document as much, and I would remember which direction (left or right) the document I want to switch to is.

With a window narrower than enough to accommodate the number of files (tabs) I have open, there seems to be little benefit to having tabs at present. I might as well just have a little box/region where scrolling the mouse cycles through files until I find the right one (or use the Documents menu). Only if the true spatial idea is conveyed meaningfully will the user be able to take advantage of the metaphor of spatially arranged "tabs".