Fix cells being erased when saving and then changing focus to another…

[rchiodo]

…… (#8482)

• Fix cells being erased when saving and then changing focus to another cell

• Make sure to use the source even if it's empty

[codecov-io]

Codecov Report

Merging #8485 into release-2019.11 will increase coverage by 0.32%.
The diff coverage is n/a.

@@                 Coverage Diff                 @@
##           release-2019.11    #8485      +/-   ##
===================================================
+ Coverage            59.14%   59.46%   +0.32%     
===================================================
  Files                  509      509              
  Lines                23390    23390              
  Branches              3774     3779       +5     
===================================================
+ Hits                 13834    13909      +75     
+ Misses                8650     8575      -75     
  Partials               906      906

Impacted Files	Coverage Δ
src/client/language/characters.ts	33.33% <0%> (+2.56%)	⬆️
src/client/common/utils/version.ts	81.48% <0%> (+3.7%)	⬆️
src/client/providers/providerUtilities.ts	88.88% <0%> (+5.55%)	⬆️
src/client/datascience/cellFactory.ts	70.51% <0%> (+12.82%)	⬆️
src/client/api.ts	92.85% <0%> (+14.28%)	⬆️
src/client/common/utils/icons.ts	100% <0%> (+16.66%)	⬆️
...cience/jupyter/jupyterDebuggerNotInstalledError.ts	80% <0%> (+20%)	⬆️
src/client/formatters/serviceRegistry.ts	100% <0%> (+25%)	⬆️
...ience/jupyter/jupyterDebuggerRemoteNotSupported.ts	100% <0%> (+25%)	⬆️
...t/datascience/jupyter/jupyterDataRateLimitError.ts	100% <0%> (+33.33%)	⬆️
... and 2 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update e558a7c...5f4156c. Read the comment docs.