Well, there's good news and bad news. The good news is that the problem with Java applications and high DPI displays is apparently fixed in Java 9: http://openjdk.java.net/jeps/263 The bad news is that Java 9 is not scheduled for release until early 2017. But, on the good news side, a pre-release version of Java 9 is available now and LXFree for Java appears to work and to scale properly on Windows 10. On the hand, having more than one version of Java installed can cause problems. And, to avoid some of these possible issues, it is necessary to run LXFree for Java from a command prompt.
If you'd like to try running LXFree for Java using Java 9, I can tell you how to do it. I can't tell you if installing Java 9 will mess up other applications on your computer. If you are not comfortable installing and uninstalling components, its probably not a good idea.
If you feel comfortable experimenting, you can download Java 9 from here: https://jdk9.java.net/download/ You don't need to install the whole JDK. Just the JRE will work. You probably already have Java 8 installed. The Java 8 runtime is located in C:\Program Files\Java\jre1.8.0_101\bin (the jre folder might have a slightly different name depending on what update is actually installed). If you install Java 9, you will have another JRE folder at C:\Program Files\Java\jre-9.
To run LXFree for Java with Java 9, you need to have the latest version, 1.7.1. Versions prior to 1.7 were bundled into a single executable file. Version 1.7 has a launcher application, LXFreeForJava.exe, which uses your installed version of Java to open a separate jar file, LXFree for Java.jar. Although this change was made for a different reason, the separate jar file allows you to run LXFree for Java with the Java 9 runtime. To do that you would type the following into a command prompt> "C:\Program Files\Java\jre-9\bin\java.exe" -jar "C:\Program Files\LXSeries4Windows\LXFreeForJava.jar"
Yo can also open notepad and copy and paste that command into a file. (be sure to include both sets of parenthesis that enclose the path to java.exe and the path to LXFreeForJava.jar.) Save the file as LaunchLXFreeForJavaWithJava9.cmd. You can then double-click this file to open a command prompt and run LXFree for Java with Java 9.
If you have other applications that depend on a specific Java version, you probably don't want to go playing around with this. If you do run into problems with Java after installing Java 9, you may need to use Programs and Features in the control panel to completely uninstall all versions of Java. Then, restart your computer. Then, re-install Java.
If this seems too complicated, you can wait for Java 9 to be released to install it. In the meantime, a partial solution is to use the Displays Control Panel and the Scaling slider to increase the size of LXFree for Java to make the menus more usable. Scaling is likely to make the display of fonts and other graphic elements slightly blurry. But, that's more usable that miniscule menus and buttons.
LXFree for Java and High DPI Displays
The LXFree for Java download page now has a link to an installer that includes a launcher (LXFreeForJava.exe) that attempts to find and use Java 9 on Windows to run LXFree for Java..
This special version allows use of LXFree for Java with a pre-release Java 9 JRE and does not require running from the command line as described in the previous post.
For the LXFree for Java executable launcher to find Java 9, the JRE should be located in the %PROGRAMFILES&%\Java\jre-9 directory.
This special version allows use of LXFree for Java with a pre-release Java 9 JRE and does not require running from the command line as described in the previous post.
For the LXFree for Java executable launcher to find Java 9, the JRE should be located in the %PROGRAMFILES&%\Java\jre-9 directory.