Fix User Experience with tab navigation

[pczarn]

• Pressing Tab may no longer trigger selection of the highlighted item, unless the user actively highlighted that item

Fixes #424

[codecov-io]

Codecov Report

Merging #430 into 2.0 will increase coverage by 0.16%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##              2.0     #430      +/-   ##
==========================================
+ Coverage   94.51%   94.67%   +0.16%     
==========================================
  Files           4        4              
  Lines         164      169       +5     
  Branches        9        9              
==========================================
+ Hits          155      160       +5     
  Misses          6        6              
  Partials        3        3

Impacted Files	Coverage Δ
src/multiselectMixin.js	96.63% <100%> (+0.02%)	⬆️
src/pointerMixin.js	100% <100%> (ø)	⬆️

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[shentao]

Finally merged! Thanks @pczarn!

[pczarn]

Yeah!!! thanks