[toolchains] Editor resets previous input sync if another input is attached to a block
How to reproduce:
- Fork a toolchain
- Create a connection from an output to an already connected input with a different synchronization channel
Results: the old connection will be synchronized with the new channel; a new connection will not be drawn.
One of the two solutions must be adopted:
- The new connection is not accepted and nothing changes
- The new connection replaces the old connection