When I try to open with text editor and soql editor, the soql editor overwrites the text editor tab (regardless of what the default is). You then have to re-open the file in the text editor format. Then the problem is that the minute you move that tab it converts back to the soql editor format if you have that format open anywhere else in vscode. This means that you either have to spend a bunch of time working around these bugs to get everything just right or you have to toggle back and forth between the text editor, soql editor, and results tabs.
VS Code Version: 1.51
SFDX CLI Version: 7.75.0
OS and version: Chrome OS - 86.0.4240.198
Thanks for the detailed feedback @rlancejohnson . This is something that we'll definitely get fixed.
cc @clairebianchi @praksb
This issue has been linked to a new work item: W-8530942
@rlancejohnson Thanks again for creating this issue, we really appreciate your feedback. We are going to look into this more but I want to make sure I understand your use case. Would it be possible to include some screenshots, a video or gif to demonstrate what it is you're looking to do?
If you would like to have the text editor and the SOQL Builder UI open at the same time you can try this workflow:

We are still looking to make this process smoother and identify any bugs in our extension or with the use of Custom Editors in VS Code, hopefully the workaround in the gif above will help you in the meantime.
I opened an issue with VS Code to get more information: https://github.com/microsoft/vscode/issues/112100
@jonnyhork Here is a video showing the main issues that I described earlier. It seems to be that the two editor types cannot co-exist in the same grid space or the text formatted tab will be converted to the soql editor format or become unclickable. Hope this helps.
Also, I test the sequence you describe and that works, so that will help in the meantime. Thanks!
As best we can tell this is a known issue with the custom editor API in VS Code. The issue can be followed in the link above and other issues referenced there. I am going to close this and follow the conversation on the VS Code repo.
@rlancejohnson Can you update to the latest version of VS Code and try your original scenario? I believe Microsoft now fixed the bug on the custom editor that was causing the issue that you reported in their latest release: Version: 1.53.0
@praksb Thanks!
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@jonnyhork Here is a video showing the main issues that I described earlier. It seems to be that the two editor types cannot co-exist in the same grid space or the text formatted tab will be converted to the soql editor format or become unclickable. Hope this helps.
Also, I test the sequence you describe and that works, so that will help in the meantime. Thanks!
https://vimeo.com/489158402/011e0b27cc