fix doc slide formatting. quiet console printing during select-drag

[disconcision]

Closes #1528, and also quiets the incessant console printing during select-drag actions.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 48.82%. Comparing base (9e0efc7) to head (2f9cd53).

Additional details and impacted files

@@            Coverage Diff             @@
##              dev    #1567      +/-   ##
==========================================
- Coverage   48.87%   48.82%   -0.06%     
==========================================
  Files         109      109              
  Lines       11947    11947              
==========================================
- Hits         5839     5833       -6     
- Misses       6108     6114       +6     

see 4 files with indirect coverage changes

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