Another NPE in Style Manager after the "performance improvements"
The specific app used to trigger this is https://bitbucket.org/shemnon/flowdown/src/6a95a474c6911376dbe10f52bbe9573640cf38d3/

Start the app via './gradlew run'
Go to the combo in the top right.
Change it once, style is not fully applied because the github style blockquote style is present.
Change it again, and giant stack trace happens (look in comments for stack trace).

The line changing the stylesheets is
https://bitbucket.org/shemnon/flowdown/src/6a95a474c6911376dbe10f52bbe9573640cf38d3/flowdown-app/src/main/java/FlowDown/FlowDownView.java?at=master#cl-114