Scenario to reproduce this issue:

1) Create some substances first.

2) Try to create a material of type Experimental, Sourced or Unified

3) Go to the Constituency section, click on + sign at the right to provide details for a constituent 

4) Enter a substance name in the search box under Title to search for that substance 

Users might sometimes see a message "No results found" in the search box under Title and nothing can be selected for the constituent.

Our Developer looked into this issue in detail and traced the problem to users entering values (e.g., substance name) with a keyboard and then hitting enter quickly rather than waiting for the search to complete. The search will be cancelled when we hit enter and instead the user should wait for autocomplete to work. The autocomplete is designed to be used as "type and wait" and is expected to be triggered just after typing one character in the search box.

If the users follow this "type and wait" method, the substance search will be successful and the application will allow the user to proceed further and define the constituency for the material they are trying to create.