Testsuite name: JavaFXCompatibility manual
Test name:graphics/api/scene/SizeTest.java
JDK version: JDK8u65b07 (64bit)
Platform: Mac10.10 x64, Ubuntu 15.04 (kwin)
Platform-specific: no
Reproducible: always

Steps to reproduce:
1. Execute attached sample
2. Press button "Left" multiple times to shrink the window.
Expected result:
- Window shrinks until some minimal possible value and then refuses to resize or throws an exception
Actual result:
- Window shrinks to minimal size, then its becomes narrow, but with screen height, then it becomes expanded.

Similar thing for Stage with negative width/height.
Probably, that is an expected behavior and negative values are kind of special predefined values like USE_COMPUTED_SIZE/USE_PREF_SIZE, but there is nothing about it in Javadoc.