Merge branch '1707-fragment-listeners' into 'master'

Don't overwrite listener references with null during fragment changes

Closes #1707, #1706, #1704, and #1697

See merge request !1227
1 job for master in 10 minutes and 16 seconds (queued for 6 seconds)
Status Job ID Name Coverage
  Test
passed #4699
test

00:10:16