A If the color changes when you long-press the canvas, it is likely that the "Quick Eyedropper" feature is activating.

You can adjust the time it takes for the Quick Eyedropper to activate or turn the feature off completely by following the steps below.

[Steps]

1. Open the "Settings" window.
2. Go to the "Gesture" section.
3. Select "Time to activate Quick Eyedropper".

Please adjust the settings to your preference.