Limit text edits and functions to a selected "mask"

Basically, I would like to make a selection of text and set this text to be a "mask" for all operations within Sublime Text. For example:

1: Select any text using the cursor or any selection tools.

2: Activate the "mask" feature (with a handy keyboard shortcut for example). The un-selected text gets a 50% darker tint to indicate the active and disabled text.

3: Now operations like Ctrl+D or "Replace All" or plugin functions will only work within this "mask" (selection), excluding all other portions of the text/data.

4: Press Escape twice to first exit Ctrl+D operation and then the selection mask.