I have just migrated from an old KiCAD (2009) to KiCAD 5.1.5.
The old version of pcbnew had a very useful feature:
When you selected a block inside the layout and hit delete, then before deleting you were asked what should be deleted (modules, tracks, vias…).
Now, it deletes just the complete block. Is this feature gone for good (like local ratsnest)?
After selecting a block right click on it and choose select -> filter selection. Tick just the tracks and then hit delete. Selection filter is more powerful tool than what was there in old kicad.