Disabling comments on tasks with specific statuses
From Planfix
With the default settings, an assignee cannot add comments to a task with the status "New" before they click on the "Accept" button:
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This is controlled by a special setting, which is located in the lower part of the additional settings for status sets window:
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If you want to allow comments to be added to tasks with the status "New," delete this rule:
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You can create any number of rules for adding comments to tasks with a certain status. For each rule, select a Task role and a task status. Users with the given role in tasks with the given status will not be able to add comments:
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Useful information
Each process has its own status set, so you can manage these rules at the process level.