Expression Buttons

An expression button applies a stored expression to your selection.

Use one

1. Select one or more properties in the timeline (not just layers).
2. Click the button.

The expression is applied to every selected property that can take one; properties that cannot are skipped, and the result tells you how many of each. The whole click is one undo step.

Create one

Click + > Add button, set the type to Expression, and write the expression in the editor.