########## begin fedora 27 output ##########
The following output is on fedora 27, Oracle JDK 1.8.201, Eclipse Photon (2018-06). It is the result of

1. eclipse
2. accept workspace in dialog box; opens to what is shown in the already sent screenshot.
3. hover on KEY_ANTIALIASING; wait for help box to appear
4. move mouse away from KEY_ANTIALIASING; problem does NOT occur
5. exit eclipse

$ export SWT_WEBKIT2=1
$ eclipse
org.eclipse.m2e.logback.configuration: The org.eclipse.m2e.logback.configuration bundle was activated before the state location was initialized.  Will retry after the state location is initialized.

(Eclipse:2423): GLib-GObject-WARNING **: gsignal.c:3492: signal name 'attributes-changed' is invalid for instance '0x7fb880e051d0' of type 'GtkTextViewAccessible'
org.eclipse.m2e.logback.configuration: Logback config file: /home/john/eclipse-workspace/.metadata/.plugins/org.eclipse.m2e.logback.configuration/logback.1.9.0.20180606-2036.xml
SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [bundleresource://509.fwk1641931089:1/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [bundleresource://509.fwk1641931089:2/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type [ch.qos.logback.classic.util.ContextSelectorStaticBinder]
org.eclipse.m2e.logback.configuration: Initializing logback

(Eclipse:2423): Gdk-WARNING **: Couldn't map window 0x7fb881df4340 as subsurface because its parent is not mapped.
$ 


########## end fedora 27 output ##########

########## begin fedora 30 output ##########
The following output is on fedora 30, Oracle JDK 1.8.201, Eclipse 2019-06. It is the result of

1. eclipse
2. accept workspace in dialog box; opens to what is shown in the already sent screenshot.
3. hover on KEY_ANTIALIASING; wait for help box to appear
4. move mouse away from KEY_ANTIALIASING; problem occurs
5. exit eclipse

$ export SWT_LIB_VERSIONS=1
$ ./eclipse
bash: ./eclipse: No such file or directory

Note: I have eclipse in my $PATH so I can invoke it directly or via an icon.

$ eclipse
org.eclipse.m2e.logback.configuration: The org.eclipse.m2e.logback.configuration bundle was activated before the state location was initialized.  Will retry after the state location is initialized.
SWT_LIB_Gtk:3.24.10 (Dynamic gdbus)
SWT_LIB GDbus firing up. Implementation v1.5
org.eclipse.m2e.logback.configuration: Logback config file: /home/john/eclipse-workspace/.metadata/.plugins/org.eclipse.m2e.logback.configuration/logback.1.12.0.20190529-1916.xml
SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [bundleresource://466.fwk116184677:1/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [bundleresource://466.fwk116184677:2/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type [ch.qos.logback.classic.util.ContextSelectorStaticBinder]
org.eclipse.m2e.logback.configuration: Initializing logback
SWT_LIB  Webkit2   Webkitgtk:2.24.3  (webkitgtk >=2.5 is Webkit2)  SWT Glue code version: 54.0 info: +BrowserFunction/GDBus, +WebkitExtension Folder versioning, +WebKitExtension OSGI support, +setUrl(..postData..), -setCookie(), -getCookie +mouseDown/Focus
$

########## end fedora 30 output ##########