Troubleshooting Common Problems
This is caused by an incorrect parent scheme setting in your custom scheme. The custom scheme file can be found in the color subdirectory of the JetBrains product you are using and the file will have the name of your scheme and a .icls extension.
For a dark scheme the first line should have Darcula as the parent_scheme attribute: <scheme name="YourSchemeName" version="142" parent_scheme="Darcula">.
If it is Default then you need to change parent_scheme="Default" to parent_scheme="Darcula". Otherwise, the IDE uses the wrong default colors from the plugin default color map. This would also affect other custom language plugins not just idea-multimarkdown.
Here is an example of a custom dark scheme with parent_scheme="Default" on the left and parent_scheme="Darcula" on the right:
This is usually caused by caches being corrupt and is not noticed after installing a new custom language plugin that requires re-indexing. Invalidate caches and restart. If the problem persists please open an issue in GitHub: GitHub Issues
JavaFx WebView preview requires JDK 1.8 that includes jfxrt.jar in the JDK's lib/ext directory, which is its standard location.
If jfxrt.jar is not found or the plugin cannot create the new editor class due to errors, it will fall back to using the JEditorPane with HTMLEditorKit preview. It will also check the Use Old Preview option in Preferences > Other Settings > MultiMarkdown so that it does not bother with the extra checks next time you open a project.
Version 1.1.7 of the plugin and later, the Use Old Preview is disabled if the creation of the new preview tab failed. It will remain disabled until the IntelliJ IDE build number changes or the Boot JDK changes, to prevent enabling the new preview with configurations that previously failed.
If you change the boot JDK, see Changing Boot JDK for instructions, and want the plugin to use the new preview, deselect the User Old Preview in Preferences > Other Settings > MultiMarkdown.
In order for the links in the preview tab to resolve to corresponding files on GitHub the file must be under a git vcs root.
Multiple vcs roots are supported. A file is considered under the vcs root that is above it in the directory hierarchy. Files with status UNKNOWN, IGNORED and ADDED are considered not to have remote counterparts.
The plugin reads the .git/config file searching for the remote origin URL. If one is found then this url is used to resolve files under this root. If the .git/config file is found but has no remote then no GitHub link resolution will be performed since these files don't have remote counterparts.
git sub-modules can also be located in the main project .git directory with a .git file in the sub-module's root directory containing the redirect for the sub-module under the parent .git directory. The plugin will read the .git file that contains a redirect for a sub-module and attempt to find the remote url in the config file there.
If you have setup the remote URL in the .git/config without a .git extension, the plugin will not recognize this repository as having a remote. Just make sure that your remote url in the .git/config or sub-module config file has a url with a .git extension and http: or https: protocol prefix.
For all files that don't have remote counterparts the links will resolve to local files. This includes files that were added but not yet committed.
Relative links from GitHub markdown documents in main the repository to wiki pages should be prefixed with ../../wiki because the documents in the root of the main repository are located at /blob/branch and wiki pages are in /wiki. The same applies to issues, pulls, graphs, pulse. Relative links will resolve to the same pages as they would on GitHub using the same relative links.
If you are clicking on a link that you expect to have a remote but a local file opens then the file does not resolve to a remote as far as the plugin is concerned. It could be because the remote origin has no URL that is an http: or https: protocol or it lacks a .git extension. Also the file should have been committed at least once so that it looses its ADDED status.