What is the ruling on singling out Sham El Nessim for fasting?

If the day of Sham al-Naseem coincides with a customary fast of a Muslim, such as fasting on a Monday, then there is no harm in fasting it. However, singling out this day for fasting because it is a holiday for non-Muslims is disliked (makrooh), as it involves glorifying days that we have been forbidden from glorifying, unless it coincides with a customary fast for a Muslim or if the fast is due to a vow or similar reason.