On what version of Ubuntu and what version of Unity.
I just checked it on 16.10 and I don't have any gaps in workspace switcher.
apt policy unity
Installed: 7.5.0+16.10.20161112-0ubuntu1
If you have gap on the right side of the screen you should open a new bug report. This as the title suggest was about gap on the left side. If you open a new bug report please specify the version of Ubuntu you are using and also Unity version. Try to determine if the problem occurs in a specific circumstances (the way to reproduce it).
On what version of Ubuntu and what version of Unity.
I just checked it on 16.10 and I don't have any gaps in workspace switcher.
apt policy unity
Installed: 7.5.0+16. 10.20161112- 0ubuntu1
If you have gap on the right side of the screen you should open a new bug report. This as the title suggest was about gap on the left side. If you open a new bug report please specify the version of Ubuntu you are using and also Unity version. Try to determine if the problem occurs in a specific circumstances (the way to reproduce it).