Each operation on the project graph is performed through a transaction. These transactions are logged in a cache. It is possible to read through this log and apply the transaction in reverse enabling undo-ing the last modifications.

It is possible to re apply the transactions previously “undone”. Yet, one a new transaction is performed (running a new RGG function, applying a modification through the attribute editor, adding an object through the menu, …) the chain of transaction do not lead to the “redo” anymore. Thus, it is not possible to “undo” > apply new > “redo”.

The commands are

• Undo changes made in the GUI,
• Redo undone actions — as long as no new operations have been performed.

Note: applying a transaction take some time. Clicking very fast between undo/redo, might trigger a transaction before the last one is properly performed. It usually lead to a NullPointerException.