My Android Studio is lastest version (Android Studio Jellyfish). I installed the markdown plugin and set up "Choose Boot Java Runtime for IDE..." but the preview tab only shows a blank screen. Markdown preview issue
I also got this issue and finally find the solution.
After set up "Choose Boot Java Runtime for IDE..." to the newest version.
The registry setting about ide.browser.jcef.sandbox.enable should be disabled.
You can also check the setting steps in this link.(Answer #61)