Label-studio: Relations between two labels on one word causes completions to not load

[ghanshyamdev]

Describe the bug
When I create relations between two different labels on the same text cause completions to not load and in the console below error occurs:

Uncaught Error: [mobx-state-tree] Can only store references to tree nodes or identifiers, got: 'undefined'
    at be (main.4c9ff345.js:sourcemap:1)
    at new e (main.4c9ff345.js:sourcemap:1)
    at t.instantiate (main.4c9ff345.js:sourcemap:1)
    at main.4c9ff345.js:sourcemap:1
    at main.4c9ff345.js:sourcemap:1
    at Array.forEach (<anonymous>)
    at t.forAllProps (main.4c9ff345.js:sourcemap:1)
    at t.initializeChildNodes (main.4c9ff345.js:sourcemap:1)
    at new t (main.4c9ff345.js:sourcemap:1)
    at ae (main.4c9ff345.js:sourcemap:1)

To Reproduce
Steps to reproduce the behavior:

1. Create a "Named Entity Recognition" project
2. Import sample task
3. Assign two different labels to the same text
4. Now select the first row from Regions and click on Create Relation and select another label from the assigned label
5. Press submit button
6. Reload the page and see the error appears in the console.

Video
The video below is very useful for reproducing the error

Environment:

• OS: macOS, ubuntu
• Browser Chrome, Firefox
• Label studio frontend version: 0.7.0

Any recommendations from you to fix this problem.

[deppp]

Hey @ghanshyamdev thanks for reporting that, we're on it

[hlomzik]

Fixed by #312 and released.
Thank you!