Nyall Dawson b6f2f7bd40 Don't use QgsVectorLayer::selectedFeatures() to check for a selection
in a layer

This is incredibly inefficient, because selectedFeatures() actually
fetches a full copy of all selected features (including all
attributes and geometry). Instead use selectedFeatureIds(), which
is just a list of numbers.

Add warning note to docs cautioning against this practice.

Fixes massive ui lockup when right clicking on a layer with
selected features in the layer tree
2018-05-28 10:59:48 +10:00
..
2018-05-16 17:26:59 -04:00