fix regression with popup selectedNode and improve types

[nightwing]

fixes #5420

also moves selectedNode from textLayer to popup to fix type annotations

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (b303256) 87.59% compared to head (047f2ac) 87.59%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5426      +/-   ##
==========================================
- Coverage   87.59%   87.59%   -0.01%     
==========================================
  Files         584      584              
  Lines       46409    46408       -1     
  Branches     7021     7021              
==========================================
- Hits        40651    40650       -1     
  Misses       5758     5758              

Flag	Coverage Δ
unittests	87.59% <100.00%> (-0.01%)	⬇️

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

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.