double clicks switch to document node buffer;

tuned;

explicit border independent of UI (cf. ad5883642a83, 2bec3b7514cf);

at least 2 worker threads to ensure some degree of lifeness, notably for asynchronous Document.print_state;

instantaneous cleanup (NB: VIEWER should be synchronous, cf. dd25b3055c4e);

unique file names via serial numbers, to allow files like "root" or multiple files with same base name;

imitate Apple in setting initial shell PATH -- especially relevant for MacTeX, MacPorts etc.;

catch PatternMatchFail exceptions in narrowing-based quickcheck

removing superfluous definition in the quickcheck narrowing invocation as the code generator now generates valid Haskell code with necessary type annotations without a separate definition

ensuring that some constants are generated in the source code by adding calls in ensure_testable