grc-qt deleting block that connects to two or more blocks leaves floating arrow lines

[chrisjohgorman]

What happened?

When replacing a block in the flowgraph then deleting one it leaves connection arrows without any associated pair of blocks. It is most easily seen in the steps to reproduce the problem.

System Information

OS: Arch Linux
GR Installation Method: Source

GNU Radio Version

3.10 (maint-3.10)

Specific Version

3.10.10.0

Steps to Reproduce the Problem

1. make a three block flowgraph. (I used constant source, throttle and null sink)
2. add a second (null) sink and connect the throttle to the null sink.
3. now add a second throttle block and connect to the constant source and both null sinks but don't disconnect the first throttle block.
4. disable the first throttle block.
   (1-4) see first attached picture
   
5. now enable the first throttle block and then delete the second throttle block
   After 5 we're left with the following flowgraph. Note the connection arrow to the first null block that is floating without any blocks connected to it.
   

Relevant log output

No response