The programmer selection is used by:
- The Tools > Burn Bootloader option.
- The Sketch > Upload Using Programmer option.
The programmer selection is not used when:
- Compiling your sketch (for example, when clicking Verify).
- Uploading without a programmer, by clicking the Upload button.
Note: In Arduino IDE 1.x, if the selected board only supports programmer uploads, the Upload button has the same effect as Tools > Upload Using Programmer