Nextcloud Mail search

Nextcloud Mail App has two search options. The first one appears at the top of the inbox but is not very powerful.
By clicking the three lines on the right corner of the "Search in folder" bar, advanced search pops up which is much more powerful.
To make search even more powerful, go to Account settings by clicking the three dots next to your email address 
Scroll down to the bottom and enable Mail body search. 
Enjoy your improved search in Nextcloud Mail!