What Is the Difference Between OK and Apply Buttons?

In any OS (Operating System), there are OK and Apply buttons.

We saw them when trying to modify some internal settings of the OS itself or an application which is installed in that OS.

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The Difference

• OK button

  Applies the changes and closes the dialog.

  Or, goes back to the previous location / one level up.

• Apply button

  Applies the changes, but keeps the dialog open, so user (we) can make further modifications.

Therefore, if we want to simply save the current changes we've made ➡️ hit the OK button.

👋 No need to hit Apply button ➡️ simply hit the OK button.

👍 Only once, hit the OK button. ✅

But, if we want to keep the dialog open, then hit the Apply button. It will perform a similar function to OK button without closing the dialog.

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How about Cancel and Close (or X) buttons?

It depends on the pop-up dialog we're at.

They can have the exact similar purpose, that is to close the dialog.

Other case, such as in a document / text editing program or other editor software, if we haven't saved the changes we made in that program, and we try to close it (by hitting the X or Close button), it will then prompt a pop-up (reminder) window to:

• Save current changes then close the program.
• Discard changes then close the program.

In this reminder (or notification) dialog, we will also see the Cancel and the X (close) buttons. The Cancel and the X (close) buttons will have the same function, that is to close the pop-up reminder dialog, and go back to the program.

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The reminder / notification / confirmation pop-up (and the buttons) is a fail-safe procedure in digital world.