[Rev 01] RFR: 8247163: JFXPanel throws exception on click when no Scene is set

[Florian Kirmaier]

> Fixing exception when clicking on JFXPanel when no Scene is set.
> 
> quick test: `./gradlew -PFULL_TEST=true -PUSE_ROBOT=true :systemTests: test --tests *javafx.embed.swing.JFXPan* --info`
> 
> It's a regression from my previous PR: https://github.com/openjdk/jfx/pull/25

Florian Kirmaier has updated the pull request incrementally with one additional commit since the last revision:

  8247163:
  Added space based on code review

-------------

Changes:
  - all: https://git.openjdk.java.net/jfx/pull/248/files
  - new: https://git.openjdk.java.net/jfx/pull/248/files/6f98aefd..6df4635d

Webrevs:
 - full: https://webrevs.openjdk.java.net/jfx/248/webrev.01
 - incr: https://webrevs.openjdk.java.net/jfx/248/webrev.00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jfx/pull/248.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/248/head:pull/248

PR: https://git.openjdk.java.net/jfx/pull/248