Added a background to the test to prevent the file from dragging onto the desktop and creating an extra file.
------------- Commit messages: - added background to prevent file creation during drag and drop Changes: https://git.openjdk.java.net/jdk/pull/8370/files Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8370&range=00 Issue: https://bugs.openjdk.java.net/browse/JDK-8202790 Stats: 8 lines in 2 files changed: 7 ins; 1 del; 0 mod Patch: https://git.openjdk.java.net/jdk/pull/8370.diff Fetch: git fetch https://git.openjdk.java.net/jdk pull/8370/head:pull/8370 PR: https://git.openjdk.java.net/jdk/pull/8370
