Hi,
First started from a clean install of local Word Press 4.8.3 on Apache 2.4.25 (x64), set the permalinks to post, installed X-Pro 1.2.4 no extra extensions no Plugins active, except WPMU DEV DashBoard. Installed Membership 2 Pro not activated went to plugins and activated came up with crazy error one liner something to do with are you sure you want to do this but no okay or continue. Clicked on plugin again to see if it activated but had not. Looked in the pages as it creates usually 4 pages with short codes inserted in them. It created one page Accounts but no shortcode. I deleted the page tried several times again same happened, I checked the database to see if it created the tables and it had so I deleted the tables and checked to see if it had created any data in the options table and had only for the form so I deleted the Membership 2 PRO in Plugins, I installed WP DB Cleaner to check for orphan records and tables and cleaned. I went to Appearance and set to default WP Theme Twenty Sixteen then installed Membership 2 PRO and all good, did basic setup of the Membership 2 PRO got it running as defaults okay.
So I thought now I will try installing X-Pro again and all good and was working okay. I then went and created a new page for login and inserted a shortcode for the membership login without going into designer updated / saved the page error again as before but flashed back to a blank new page but had saved the Login page with the short code and could view no problem. I opened the Login page again copied the cleared the shortcode went into the Cornerstone designer, dropped in a section added a text element added the shortcode into the html edit section, no problem, previewed okay, saved it checked from front end and okay went back into Cornerstone to format the page with like center and added some other text, Saved and okay, went and made a coffee, celebrate the achievement and came back and there was a dialog saying;
A conflict on the front end of your site has prevented the preview from loading, Button TRY AGAIN, I clicked on the button the logo throbbed away for a while then same message. Went back to dash board and tried again but same thing, blank page this time. Since I have tried 3 other membership plugins WP eMembers, MemberPress, Ultimate Membership Pro all had similar problems but WP eMembers was the least trouble.
Another point, more of a cosmetic thing with Cornerstone with the button bar on the left, mostly the save button with the Chrome window maximized on a 4k monitor runnin the font size at 150% hard to get to the Save button at times as the Windows 10 toolbar pops up from time to time, yeah I know have the toolbar fixed I know but I like it hidden as not as distinctive. Otherwise I love the new X-Pro once you get your head around it.
Cheers.
Rob.