I can also reproduce this issue fairly easily in modeler V6.10.10. Steps to reproduce:
1) open any project
2) open any page or create a new page
3) Make sure at least one other tab is open in the modeler
4) start typing in an empty container (the modeler automatically creates a new "Text" item for you)
5) Instead of clicking somewhere on the page itself to confirm the new Text, click on one of the other open tabs directly
-It does not matter if you do this inside or out of a dataview
-My modeler preferences are fairly default apart from the timeout waiting for error checks (i have not detected a setting that would fix this issue yet)
I have never encountered this. Could you create a video of this to share? And you could create a support ticket for this.
When you say: If I type/ change some text in a text box and then immediately (from there) try to open another tab
Do you mean in the modeler or the web application??