HTML editor vanishes from page after u/g

[hameau]

... as the HTML editor now flashes up briefly and then vanishes from any page I'm editing or creating.

Try commenting any custom settings in gsconfig.php that you have for these two parameters:

Code:

#define('GSEDITORTOOL', 'advanced');

#define('GSEDITOROPTIONS', '');

I can't remember exactly what I found was causing similar symptoms when I upgraded. Re-introduce your custom settings one at a time to see what breaks it.