In the application that I'm currently working on, the user is allowed to make changes to a subset of data from an external data source. Changes are made using basic or custom controls such as Toggle Buttons, Text Boxes, and Sliders. Changes made to the data source by the user are actually not submitted to the data source until the user confirms or cancels the changes.
Visual feedback should be displayed should the control (eg. ToggleButton) detects a change in value and is pending submission or cancellation. My question then becomes, how best should this be indicated?
My current idea is to have a flag that appears in the corner of the control with maybe an common icon (example below). However, is there a standard icon for this? An asterisk (*) icon was considered because it often means a file has been modified and is pending a save. However, I figure that might be confusing on controls because generally an asterisk is used to indicate a requirement of a field.
Below is an example of how a button might look with the "changed" flag in the corner of it.