ADDITIONAL SYSTEM INFORMATION :
Microsoft Windows [Version 10.0.17134.165]

JDK under test: C:\\Program Files\\Java\\jdk-10.0.2
java version "10.0.2" 2018-07-17
Java(TM) SE Runtime Environment 18.3 (build 10.0.2+13)
Java HotSpot(TM) 64-Bit Server VM 18.3 (build 10.0.2+13, mixed mode)

A DESCRIPTION OF THE PROBLEM :
The test java\awt\datatransfer\MissedHtmlAndRtfBug\MissedHtmlAndRtfBug.html fails on Windows with the message "Error. Drop did not happen. Target frame is possibly covered by a window of other application. Please, rerun the test with all windows minimized."
It also fails if all windows are minimized.
The issue was also observed on MacOSX

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
>java -jar jtreg\lib\jtreg.jar -ignore:quiet -v -a -xml -testjdk:"C:\Program Files\Java\jdk-10.0.2" -javaoptions:"-Djava.awt.headless=false" test\java\awt\datatransfer\MissedHtmlAndRtfBug\MissedHtmlAndRtfBug.html

ACTUAL -
#section:applet
----------messages:(4/213)----------
command: applet MissedHtmlAndRtfBug.html
reason: User specified action: run applet/othervm MissedHtmlAndRtfBug.html
Additional options from @modules: --add-modules java.desktop
elapsed time (seconds): 24.646
----------System.out:(0/0)----------
----------System.err:(6/674)----------
java.lang.RuntimeException: Error. Drop did not happen. Target frame is possibly covered by a window of other application. Please, rerun the test with all windows minimized.
at MissedHtmlAndRtfBug.verifyTestResults(MissedHtmlAndRtfBug.java:110)
at MissedHtmlAndRtfBug.start(MissedHtmlAndRtfBug.java:78)
at com.sun.javatest.regtest.agent.AppletWrapper$AppletRunnable.run(AppletWrapper.java:158)
at java.base/java.lang.Thread.run(Thread.java:844)
STATUS:Failed.Applet thread threw exception: java.lang.RuntimeException: Error. Drop did not happen. Target frame is possibly covered by a window of other application. Please, rerun the test with all windows minimized.

---------- BEGIN SOURCE ----------
http://hg.openjdk.java.net/jdk10/jdk10/jdk/file/777356696811/test/java/awt/datatransfer/MissedHtmlAndRtfBug/MissedHtmlAndRtfBug.java
---------- END SOURCE ----------

FREQUENCY : always