I am working on a related action and while working on a related action I don't want anyone to work on that related action

How I have implemented this feature is using this plugin -  Text Cache. It allows you to store a value in the server's cache memory. So here is what you need to do

1. Identify the name of the key you want to create Rg. AddUserRelatedAction.
2. Now using the above plugin, set your username (loggedInUser) in this key using the plugin in a local variable as the screen loads. 
3. Now check if the local variable has a value, then show the contents of the screen otherwise keep it hidden. 
4. When the user submits the form, set the key back to null. 

This way, when the key has a value, someone is using it. If it doesn't have a value, no one is using it. 

Hope it helps!

FYI - don't use that text cache plugin in an HA environment.

Honestly, no clean way to do this. Mike's approach also has some caveats, people need to complete or cancel. Though, you could implement something like Appian does for process models by notifying the user that someone has taken the task and give them the option to kick them out. 

definitely - and/or you need to implement a strict (and probably relatively cruel) task timer - at least for actions with a high possibility of this sort of collision.

Mathieu Drouin said:

people need to complete or cancel.

definitely - and/or you need to implement a strict (and probably relatively cruel) task timer - at least for actions with a high possibility of this sort of collision.

Mathieu Drouin said:

people need to complete or cancel.