If you use the "Ignore Agreements" checkbox to override the SLA matrix or come from a HelpDesk background and miss the "Toggle Customer Linking" button when selecting users and CI items then you may want to know how to disable/override other dropdowns too.
Here is a handy bit of filter design that'll do the same for any filter in Service Desk 7.2 onwards...
In this example we'll override the out-of-the-box user/group/role filters that are on the Process Assignment object and are used to filter the dropdowns on the Assignment windows so when you select a group you get the User dropdown filtered to only show users within that group. I will create a "Disable User Filter" checkbox when will allow the User dropdown to show the full list of users instead on the fly.
1. Open Object Designer and on the Process Assignment object create a Boolean attribute named Disable User Filter.
2. If using from version 7.2.6 set the Default Value property to False.*
3. On the User attribute open the Filter Selectors window.
4. With the Users by Group and Role filter selected in the list press the New Condition button.
5. In the attribute tree at the bottom left of the window check the box next to Disable User Filter.
6. In the text box to the right type False and then press the Apply Condition button. See the screenshot below for how the window should now look:
7. Click OK to save the settings then press Save in Object Designer to commit these changes to the object.
8. Open Windows Manager and open your Incident Assignment (or Change Assignment, Incident Task Assignment etc..) window.
9. Add the Disable User Filter checkbox to the window and press Save.
Now open an incident and use the Add Assignment action. Select a group and the user list will be filtered, check the Disable User Filter box and now the user list of unfiltered! You can use filter conditions like this to swap between different filters too by adding more filters to the same attribute with different filter conditions (ie. one filter if the checkbox is False, a different filter if it is True). This adds another dynamic level and can make for very flexible filtering.
* It is important that the checkbox is False and not NULL for this method to work. In versions prior to 7.2.6 you can still have this value pre-populated with a False by editing the assignment action instance in the process and checking then unchecking the box. The only downside of this method is you must also pre-populate any mandatory fields including the Title. This may actually already be pre-populated as is a common setup.