File nesting dialog
JetBrains Rider provides a default configuration of file types and typical suffixes that are used for related file types — for example, a file with the .map.ts suffix is normally related to a file having the same name and the .ts extension — such files will be automatically grouped in the Solution Explorer.
You can configure these relations or disable logical nesting altogether by clicking on the toolbar of the Solution Explorer and choosing File Nesting:
Grouping of files in this way will not make any changes in your project/solution config files.
Show files with the same names as nested
Add a new row and specify the "parent" file suffix and the matching "child" file suffix. List all patterns explicitly without using wildcards or regular expressions.
Remove the selected rule from the list.
Reset to Default
Discard all your custom patterns and reload the default rules.