As of version 2017 R3 each test or standalone code file could be set into 'In Development' state. If the test includes a code file it will be automatically set to 'In Development' along with the test.
Each test marked as 'In Development' will be displayed in red in the Project Explorer. If the test includes a code file its name will be also coloured in red.
Load and Manual tests could not be set 'In Developement' as these do not require compilation.
If a test flagged as 'In Development' is included as a test as step in any other test it will be always attemped to be executed regardless of its current state.
Any tests could be included in a test list. These marked as 'In Development' will be coloured in red also in the 'Create New Test List' wizard.
Depending on the test list setting 'ExecuteTestsInDevelopment' the tests marked as 'In Development' will be either skipped or executed for both local and remote run. The default behavior is these to be skipped.
To remove the 'In Development' flag select the 'Remove' option from a test's context menu in the Project Explorer.