New issue 945: Adding multiple sets of annotations to a slice is slow https://bitbucket.org/yt_analysis/yt/issue/945/adding-multiple-sets-of-annot...
If I open a large dataset and create a slice, then add density contours, followed by text annotations, the text annotations take a very long time to add.
If I add the text annotations before adding the contours, it's much faster.
If I add multiple sets of density contours, each set takes progressively longer.
Nathan Goldbaum has suggested that implementing caching would alleviate the issue.