When the button is clicked the current record is saved in case the associated process is set as auto save. This event occurs when the button is pressed, not when the process is going to be executed (a popup window is shown requiring more information).
If the save process fails an error message will be shown in the popup window. And the rest of options for the process will not be displayed making impossible to launch the process. The user will have to close the popup, edit the incorrect data and click the button again.
In case the popup window is closed without performing the action the data is already saved.