Fix blank column issue.

[jsoules]

Suggested addition to scatterplot fix branch, to correct "empty spacer column" issue.

Before (in scatterplot-fix branch):

After (this branch):

[codecov-commenter]

Codecov Report

Merging #71 (500fff1) into scatterplot-matrix-fix (1428778) will increase coverage by 0.00%. The diff coverage is 0.00%.

@@                  Coverage Diff                   @@
##           scatterplot-matrix-fix     #71   +/-   ##
======================================================
  Coverage                    7.07%   7.07%           
======================================================
  Files                          72      72           
  Lines                        5653    5652    -1     
  Branches                       78      78           
======================================================
  Hits                          400     400           
+ Misses                       5253    5252    -1     

Flag	Coverage Δ
gui_units	8.72% <0.00%> (+<0.01%)	:arrow_up:
svc_units	2.27% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
src/tabs/ScatterplotsTab.tsx	0.00% <0.00%> (ø)

:mega: We’re building smart automated test selection to slash your CI/CD build times. Learn more

[jsoules]

(Sorry, didn't realize I had a slightly different set of variables selected for one of the screenshots. I'd been confirming that everything still worked correctly when we had too many variables selected.)

[magland]

Yep this looks good to me. Ready for merge and deploy I'd say.