When editing inside a long org-mode block (#+BEGIN_.... - #+END_....) Emacs is really slow (it can take several seconds to write a single character), while editing the rest of the buffer takes normal time.
I found this (org-mode 9 too slow with long code blocks) which is related to source blocks (whilst my problem is with "custom" blocks: #+BEGIN_exercise, #+BEGIN_solution, #+BEGIN_theorem,... which have no direct meaning in org) and found that also in this type of blocks the problem is the syntax highlighting:
M-x profiler-start
Type a character in the code block
M-x profiler-report
- redisplay_internal (C function) 1498 68%
- jit-lock-function 1492 67%
- jit-lock-fontify-now 1492 67%
- jit-lock--run-functions 1492 67%
- run-hook-wrapped 1492 67%
+ #<compiled 0x155edb4743f1> 1492 67%
But inside these blocks I write common org syntax, so it's not needed to call jit-lock to highlight it: is there a way to enable it only for source blocks?
Maybe if exporting an heading as a block could be possible (Is it possible in org-mode to export a * heading to a \begin{heading} \end{heading} block construct?) it can be a solution.
