+ \item It is not possible to switch Motion cache off. While working, \textit{Motion} always looks in its cache. If it contains some data assigned to the current frame numbers, that cached data will be used unconditionally. If not, that data will be calculated, stored in the cache, and later reused, also unconditionally.
+ \item In the Motion plugin dialog there is a button \texttt{Clear tracking file contents}. When in doubt, you can press this button, the cached data will be erased and fresh recalculated on the next pass.
+ \item It is quite usual to wish independent caches for different parts of video. It is possible to set such distinct cache file names (either manually, or let software generate them with \texttt{Generate tracking file name}). When you generate new names, the plugin automatically switches Calculation off, just for security. You switch it on again when needed.
+ \item If \texttt{play track} is switched off for the track where the Motion plugin was attached, the plugin will calculate nothing. Also, if \texttt{Play every frame} was not active in \texttt{Preferences}, some video frames can get skipped from processing.