Sprotty: On clicking "Open in Diagram" from right click options in yaml file, why is diagram not opened in new tab on right side?

[Samridhiseth]

If we open a yaml file in sprotty, and then right click on the file to select "open with neural network graph" option, the sprotty diagram tab doesnot open on right side in a new tab. It gives error: Referenced widget is not in the layout (Screenshot attached). But, if we edit the file once and save it and then select "open in with neural network graph" options on right click, the diagram is opened on right side in new tab.
It should open in new tab even without editing.

[JanKoehnlein]

Can you give more information about what Theia extension you're using? Sprotty is just the underlying framework.