I am using Standard theme of Moodle and I have checked the core.css. It does contain the .texrender line. Do I have to insert the above lines in other css files under style folder for standard theme? Nevertheless, I purged all cache. However, still I get a lot number of blank rows before any equation. Sorry bothering.
Dragmath equation editor inserts number of blank lines before it appears
Then it's caused by something else - no need to add that css.
What preview window is it? Quiz/some question type/some activity?
Do you have any custom plugins ( 3rd party blocks etc ) installed? Sometimes different 3rd party activities use the same css classes for different things...
I have installed moodle on Fedora 17. I do not know if the problem of equation display right at the bottom relates to some other file not directly connected with moodle.
On CentOS 6 the same thing is working well.
Is there any other easier way to install some other equation editor if not dragmath? I will be grateful for response.