I've installed the latest Extension Library on my designer machine and my server. If I do "tell osgi..." at the server, I get, among other things...
[1130:0002-0BDC] 10/26/2016 05:16:58 PM 13 ACTIVE com.ibm.xsp.extlib_9.0.1.v00_17_20160428-0214
[1130:0002-0BDC] 10/26/2016 05:16:58 PM 36 ACTIVE com.ibm.xsp.extlibx.theme.bootstrap4_9.0.1.v00_16_20160119-2239
I've enabled com.ibm.xsp.extlib.library and com.ibm.xsp.extlibx.library in my application. I don't see the org.openntf.xsp.bootstrap.library as a choice, but I think that's to be expected. I have read that bootstrap is now baked in to the ExtLib.
There are no Bootstrap themes available in the theme dropdown. I entered "Bootstrap3.2.0" manually, and my application does load the Bootstrap framework.
The big problem is that when I drag the Application Layout control onto a custom control, I don't get the "Bootstrap Application Layout" option. I just get "Basic... and "OneUI..." What am I doing wrong? Do I need to install the Bootstrap4Xpages plugin as well? Other posts on this topic come close, but I haven't found anyone with this exact issue.