avoid -Infinity which confuses JFreeChart histogram;

Isabelle-hg: http://isabelle.in.tum.de/repos/isabelle@51370 716a94cc5aaf1f4dbc11c11f26b2fca946020e80
support for 'chapter' specifications within session ROOT;

Isabelle-hg: http://isabelle.in.tum.de/repos/isabelle@51397 03b586ee5930d726ddb2b5af0b5670bbe58267cb
discontinued "isabelle usedir" option -r (reset session path);
simplified internal session identification: chapter / name;
clarified chapter index (of sessions) vs. session index (of theories);
discontinued "up" links, for improved modularity also wrt. partial browser_info (users can use "back" within the browser);
removed obsolete session parent_path;

Isabelle-hg: http://isabelle.in.tum.de/repos/isabelle@51399 6ac3c29a300e5d57effc59c5f14b7ca6ce8a4452
include session description in chapter index;
prefer alphabetical order;

Isabelle-hg: http://isabelle.in.tum.de/repos/isabelle@51402 b05cd411d3d3d833b486a7e4dd3cee8dde2fa81d
proper path -- I/O was hidden due to permissiveness;

Isabelle-hg: http://isabelle.in.tum.de/repos/isabelle@51406 950b897f95bb206049d815e3f383ba11fe56c3d5
do not absorb I/O errors;

Isabelle-hg: http://isabelle.in.tum.de/repos/isabelle@51416 e2505a192a7c8ef20776180efdfe37cb2661a749
more accurate handling of global browser info at the very end (without races), subject to no_build and info.browser_info;

Isabelle-hg: http://isabelle.in.tum.de/repos/isabelle@51418 7b8ce84033409a7bae1657ae9e4655e5b64e1f2b
clarified parallel_subproofs_saturation (blind guess) vs. parallel_subproofs_threshold (precient timing estimate);
clarified unknown timing vs. zero timing;
tuned;

Isabelle-hg: http://isabelle.in.tum.de/repos/isabelle@51423 e5f9a6d9ca82e81c22e4d89299fa2e5c9ec8c297
simplified time_CPU and time_GC;
derive relative speed from time (considered as step function);

Isabelle-hg: http://isabelle.in.tum.de/repos/isabelle@51432 903be59d96650e072f0d9b6fa4dd895d88f77c8e
more precise tooltip window size (NB: dimensions are known after layout pack, before making content visible);
more precise margin width based on fractional Pretty.char_width (avoid multiplication of rounding errors);
early initialization of gutter to get proper text area painter size (see also 2585c81d840a);

Isabelle-hg: http://isabelle.in.tum.de/repos/isabelle@51439 b10b64679c5b13b94f09e2401173542f6d2f9716
some more hammering to convince JDK 7 (and 8-ea) on Mac OS X about window size change;

Isabelle-hg: http://isabelle.in.tum.de/repos/isabelle@51440 c5605f3c84b0283c52fce397540a6af1c0a2705f
more elementary tooltips via mouse events (imitating parts of javax.swing.ToolTipManager) -- avoid abuse of getToolTipText to produce window as side-effect;

Isabelle-hg: http://isabelle.in.tum.de/repos/isabelle@51441 37f699750430e2b58d4562120de3be92ae18b9bc
explicit handling of tooltip window stack -- avoid memory leak due to not-so-weak references to disposed windows (via event handlers and other aux. components);

Isabelle-hg: http://isabelle.in.tum.de/repos/isabelle@51449 8d6e478934dc0df1264340f791d42f36c05605ce
re-init last window without flipping its visible/disposed state, to avoid odd focus inversion problems;

Isabelle-hg: http://isabelle.in.tum.de/repos/isabelle@51450 a8e3a72b348c42f51e8d3d9808c65cf88e7ace64
recovered special background handling from 8d6e478934dc, particularly relevant for gutter border;

Isabelle-hg: http://isabelle.in.tum.de/repos/isabelle@51451 e4203ebfe750900c4aefc2757cfb9118c7b9e695
extra tooltip_delay after window.dismiss operation, to avoid flickering of quick reactivation;

Isabelle-hg: http://isabelle.in.tum.de/repos/isabelle@51452 14e6d761ba1c1caf8f11bce3cfb31758ea8b89c4
proper parent component for window.init;

Isabelle-hg: http://isabelle.in.tum.de/repos/isabelle@51457 66824fea1a72a47a0195f16e8cf3a5dd32581223
prefer ownerless window, to avoid question of potentially changing parent view;

Isabelle-hg: http://isabelle.in.tum.de/repos/isabelle@51458 67542078fa2159f2e0b5d076d9eb1313142616f0
eliminated char_width_int to avoid unclear rounding;
clarified integer conversion for margin;

Isabelle-hg: http://isabelle.in.tum.de/repos/isabelle@51469 18120e26f8187fd059eaeda806f3162e8fe0bad0
proper metric for blanks -- NB: 70f7483df9cb discontinues coincidence of char_width with space width;

Isabelle-hg: http://isabelle.in.tum.de/repos/isabelle@51470 a981a5c8a505f895fdae2b9ae83a42532b730a18