Be sure that:

1. The Caché/Ensemble/HealthShare/InterSystems IRIS instance that you are trying to connect to is version 2016.2+.
2. Your web server (listening on the web port that you provide in the Server Connection Configuration dialog) is configured to handle requests starting with /api/atelier. The Atelier documentation explains how to do this for an IIS web server here, but the same principle applies to all web servers. Atelier makes REST requests to communicate with the server and those will start with /api/atelier instead of /csp like many other CSP requests.
3. The /api/atelier web application is enabled at the Caché level. To do this:
   1. Launch the System Management Portal and select System Administration > Security > Applications > Web Applications
   2. Select the /api/atelier application
   3. Check the Enabled boxes for Application and CSP/ZEN and Save

If you are still having trouble I would suggest reaching out to InterSystems Support (email support@intersystems.com or call +1 617-621-0700).

Lucas - Thanks for looking into this and posting your findings here. You can get errors like this in Atelier for long-running compiles. The development team is aware of and looking into it.

Starting with Atelier 1.2, there is a new tabbed editor for BPL/DTL. Open the class file from the Atelier or Server Explorer, which will display the class code by default. At the bottom of the editor there should be a tab for either BPL or DTL that you can click to display the graphical editor:

The "Open diagram editor" option should not be there in Atelier 1.2. I am guessing that you were trying to open the graphical editor by right-clicking the class and selecting Open With > Other > Atelier BPL Editor. But that is not the correct way to view the BPL/DTL graphical editors. 

If you are still having trouble I would suggest opening a WRC case with InterSystems Support (email support@intersystems.com or call +1 617-621-0700) so that an advisor can dial in with you and take a look.

There is an existing request with development to improve the usability of XData blocks in Atelier. I added a note to that request, linking to this DC post, asking to consider the auto spacing/indentation as well. The request for XData usability improvements has not yet been roadmapped.

I've been working with Lucas S. on this in a WRC case. We believe that the source of the issue has to do with the encoding of the file, as compared to the file's contents and the encoding of the Eclipse workspace/Atelier Project/file in Atelier.

Copying this problem file into an Eclipse-only (non-Atelier) project does result in display issues until the file's encoding is changed within Eclipse. To change a file's encoding you can right-click the file in the Atelier or Project Explorer, click Properties and change the "Text file encoding" settings under the Resource section.

While there are workarounds*, you should be allowed to import these files into an Atelier project. The Atelier development team is reviewing this.

*Workarounds we've found in our investigation:

• Run an iconv command on the file on disk to change its encoding
• Change accented characters to their corresponding HTML entities, https://developer.mozilla.org/en-US/docs/Glossary/Entity
• Manually copy the HTML file from the CSP physical files directory into the Atelier project directory on disk, then change the file's encoding within Eclipse to avoid display issues

After upgrading to Atelier 1.2, did you run into the issue described in the DC post here? If so you may have Googled and found information about adding -clearPersistedState, or something similar, to one of the Eclipse configuration files. However if a setting like that is left around in the config file, it could result in Eclipse not persisting data across shutdowns since that setting will be read back in each time you start Eclipse back up.

There are no plans to implement an equivalent to the Studio SQL Storage GUI in Atelier. The use case for the SQL Storage editor is to maintain legacy applications. The development team's primary focus with Atelier is to support new/more modern development.

If your day-to-day work requires the use of the the Studio SQL Storage GUI, the InterSystems recommendation is that you continue to use Studio.

Thanks for this question, I think it's one that a lot of Atelier users will have. In general we recommend storing each of the different projects that you are working on, or closely related pieces of those projects depending on their size, in their own Caché packages. That helps when you are using source control, as you can pull down just one or a few packages from source to work on in Atelier, rather than having to pull in an entire source code repository.

The main considerations with Atelier will be:

1. You do not want to have too many files in a given Atelier Project, as this can cause performance problems. (Unfortunately I cannot put a number on this, since it really depends on the size and complexity of those files.) An Atelier Project can be thought of as containing a unit of work - maybe it's the set of files you need to edit to implement a particular new feature.
2. To help with the potential performance problems I mentioned in #1, working sets will be your friend. This is an Eclipse concept - a working set groups together elements and allows you to restrict the resources that you are viewing. In turn that will limit the background processing done on files/projects not in an active working set. This is discussed in the Eclipse documentation here. There is also some information about that in the Atelier-specific docs here.

We'd love it if you could post more about your experiences, since this is something that effects many users. You can note that in a comment here, or preferably write up a new article and post it on the Developer Community as an example for other users!

Atelier is an Eclipse plug-in, and is therefore should be compatible with platforms supported by Eclipse. Eclipse Oxygen's target environments can be found on the Eclipse website here.

To second Fabian, this process can be made easier by making use of Atelier projects.

You can think of an Atelier project as a place to store a unit of work. An Atelier project will typically store all of the files directly related to a particular application, feature, etc. Each Atelier project is configured with a server connection and namespace where code can be compiled and run. You do not necessarily need to create a new project each time you launch Atelier or add something to source control.

There are a number of videos on the InterSystems Learning Services website on this topic (using Atelier with Git/source control). A few that I think will be the most useful:

• Atelier: Create a New Project and Add to Source Control (demo that starts with creating a new Atelier project then connects that to a remote Git repository)

• Atelier: May the Source Be With You (a presentation from Global Summit 2017 about using Atelier and Git, followed by a demo similar to the video above)

• Moving From Studio to Atelier (a presentation from Global Summit 2017 about migrating to Atelier, specifically for former Studio users, with a lot of good information on source control)

You may also want to take a look at the Learning Services course catalog. You can filter this by videos related to Atelier. There are a lot of great introductory and more in-depth videos.