Uninstalling: 4chan X disables the native extension, so if you uninstall 4chan X, you'll need to re-enable it. To do this, click the [Settings] link in the top right corner and uncheck "Disable the native extension" in the panel that appears.
Private browsing: 4chan X does not yet support private browsing mode. Although it may work in this mode, browsing data recorded by 4chan X, such as your last read post in a thread and which posts are yours, will need to be cleared manually by resetting your settings.
+Private browsing: 4chan X does not yet support private browsing / incognito mode. Although it may work in this mode, browsing data recorded by 4chan X, such as your last read post in a thread and which posts are yours, will still need to be cleared manually by resetting your settings. To control what browsing data 4chan X records, use the Remember Last Read Post and Mark Quotes of You options in the settings panel.
HTTPS: 4chan X currently shares your settings and post history between the HTTP and HTTPS versions of 4chan. If you are concerned about protecting your privacy against a man-in-the-middle attack, you should disable 4chan X on the HTTP version of 4chan and/or install HTTPS Everywhere.