The opening of a Flamingo Theme for edition is slow by design, since there is a LESS compiler execution on the client-side.
- the LESS compiler is executed several times when the page is loaded, 3 times instead of 2 (a second compilation is needed to take into account the variables holded by the theme).
- the "curtain" hiding the preview window is blinking between these computations.
These 2 aspects could be improved.
I first wanted to describe this issue as a bug called "Editing a Flamingo Theme is too slow" but I realized that, even with this improvement, it will still be slow (but a bit less ).