If during WebKitX installation you get an error message that WebKitXCEF3.ocx and cmax40.dll failed to register, it most certainly means that Microsoft x86 C++ 2015 Redistributable Package failed to automatically install because the Windows OS version and/or its current Service Pack are not compatible with the included Microsoft x86 C++ 2015 Redistributable Package. You are advised to download Microsoft x86 C++ 2015 Redistributable Package for you Operating System and Service Pack bundle, and install it manually.
WebKitX ActiveX provides OLE Control Host Window Handle (HWND) to Chromium Embedded Framework (CEF3), which in turn paints the HTML5 composite image to the OLE Control Host Device Context (HDC). This mechanism requires you to Disable Double Buffering Features of the Host Form or OLE Control Host. Furthermore please make sure you set the scale mode of your Host Form or OLE Control Host to Pixels.
WebKitX due to JavaScript injection features and extensive use of Eval() requires Content Security Policy (CSP) to be suppressed. If you try to load a site with CSP enabled in WebKitX, it will result in a series of error messages related to unsafe-eval. Please refer to Content Filtering article above for information how to by-pass CSP in WebKitX.
JavaScript in WebKitX is disabled by default and as a result most sites will not load properly. Please handle the OnBrowserReady event and enable JavaScript by setting WebKitX1.DownloadScripts = True.
WebKitX Content Filtering features and SSL Client Certificate enabled on your Web Server cannot work together, by design. You must either disable WebKitX Content Filtering or disable SSL Client Certificate on your Web Server. Please note this has nothing to do with HTTPS. For more information please refer to Content Filtering chapter.