With Mathematica 13, it seems that all these headaches and sufferings from Workbench are gone. Take a look at https://community.wolfram.com/groups/-/m/t/2427576?p_p_auth=SSI9jMrH

I believe the most recent Wolfram plug-in for Eclipse is version 10.1.1087. A case initiated because of Eclipse builds failing on missing files was resolved with a plug-in update to 10.1.1087: use Help : Check for Updates to see and download the current installed version and download an update for the plug-in in Eclipse.

Also recently PacletInfo.m key word MathematicaVersion has been replaced with WolframVersion. All my PacletInfo.m files started generating a warning on MathematicaVersion. See https://reference.wolfram.com/language/ref/PacletObject.html.

just checked, workbench and core have different versions on my system.

@Masso Chailly Thanks for the heads up. I think I'll stay on 12.1 and the previous Workbench for a bit longer. It's not great, but it's functional.

I did (well, the build number of what I tried is 10.1.1065 from the technical support). I think it does provide emergency fixes of the issues with Mathematica v12.2. At least, it works, more or less, for my custom documentation files. However, several glitches are still noticeable immediately:

• The DocumentationTools palette has several bugs (e.g., putting “Example Delimiter”)
• The ".wl" file extension is not supported for PacletInfo (it must be PacletInfo.m).
• It does not respect/recognize the recent formats/fields of PacletInfo.wl.

I'm just a normal user, but luckily, can afford for the technical services. I don't know why the build number of mine is slightly higher. Maybe the difference is not big. My impression from various Internet blog/forum posts is that building custom documentation files, probably the main purpose of Workbench, is highly non-trivial and requires lots of external resources like Java, etc. Maybe too technical for end users like me. Maybe that's why the public release of Workbench is lagging behind Mathematica.

One piece of good news is that they are gradually improving the DocumentationTools (it already works pretty well just with Mathematica, even better than with Workbench in some sense) and DocumentationBuild within PacletTools starting from v11.x, and I notice that with v12.2 those codes are sort of getting matured. I hope, some day, we can build the mid-scale documentation files (I'm dealing with 500+ files) without Workbench. Today, I heard the announcement of v12.3. I just hope that things got improved.

@martijn has shared his similar troubles: https://community.wolfram.com/groups/-/m/t/2214983 I leave a remark here because the issues are clearly from the outdated Workbench.

I have contacted WRI, and they confirmed the issues. They say that the developers are working on a fix and a new public version of Workbench is coming sooner or later. Well, it was about a month ago.

What I noticed was that the documentation pallet was not available in 12.2 unless I started Mathematica from eclips and the errors pointed to the lack of these tools. In the MathematicaSources of workbench the DocumentationTools and DocumentationBuild were present.

I didn't dare put the resources from Workbench distribution to the system installation directory. In fact, I am doing the opposite. I use DocumentationTools coming from Mathematica 12.2, which looks better and easier to launch even without Eclipse/Workbench, to edit my documentation files. Then, I build them using Eclipse/Workbench.

My Workbench version, which I obtained directly from WRI, is slightly higher than the public version. It is still outdated and problematic. It just builds my documentation files -- I cannot even edit my files within it.

There is DocumentationBuild as a sub-package of PacletTools of Mathematica 12.2. I was thinking of directly -- without Workbench -- using it to build my documentation. No luck yet.

As it is, making integrated documentation is too much of a headache, at least, for the moment. I have an impression from Mathematica 12.2 that they are trying improve it by integrating the required tools right into the system. I hope this transition period ends soon.