Hi, Strange one this. A core going to 100% and staying there. This happens to me occasionally and I've noticed other users experiencing something similar. Ok, so I just save my work and close Kdenlive and it retreats back to normal...re-load and all's fine.

How it happened just now:-

Load Kdenlive
New project - add five clips - proxy all.
Add title clip - click OK
Title clip appears in monitor
Core goes to 100%

(Obviously not all the time)

0.8.1+svn20110715.r5793-0ubuntu0~sunab~maverick1
0.7.3+git20110715.20fa0adf-0ubuntu0~sunab~maverick1