Question

Redo button is enabled only after the _button has been used at least
once.
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Answer 1

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Answer 2

Answer:

Undo and Redo Functions

Studio lets you undo and redo project-level changes (for example, changing text in a Properties Grid field, creating a link on an automation, or deleting a control in Object Explorer). These functions do not apply to project-level changes (such as adding an adapter) or solution-level changes (such as adding a file).

You can choose the Undo and Redo buttons from the main toolbar:

These buttons are enabled when there has been a change that can be undone or redone. The shortcut keys Ctrl+z and Ctrl+y apply. Pressing Ctrl+z undoes the most recent change. Pressing Ctrl+y reapplies the last (undone) change.

Undo/Redo list of changes

Clicking the arrow next to either the Undo or Redo button lists the changes that can be undone or redone. For example, the example below shows the Undo options after the following changes have been made on an automation:

Variable design block moved

Data link changed to Sensitive

Event link changed to Asynchronous

Note that the changes are listed in reverse chronological order. In this case, to undo the first action, Move Connection Blocks, you must first undo the Asynchronous link change, then the Sensitive link change, and finally the Move Connection Blocks. You can select multiple changes to be undone or redone.

The changes listed in the Undo/Redo lists continue to grow as long as the Designer has focus on the project item. Referring to the list shown in the image above, this list will continue to grow as long as the automation is open in the Designer and changes are being made to the automation. This list stays intact even when the project item tab is not in focus in the Designer. However, closing the project item in the Designer clears the list of changes associated with the item.