That’s correct, if you have showHeader = false, the sidebar will never appear.

Lots of our users really like the sidebar, mostly for the recently viewed records. There’s a few tips out there for redoing the recently viewed aspect of the sidebar, but most of them fall short in my opinion - I haven’t seen any, for example that make use of the nice icons for the different object types. Would be a nice tutorial for Skuid to release, re-creating the Salesforce sidebar. 

Also, trying to reproduce the sidebar causes a problem with OpenCTI not being displayed…

Mathieu,

With the Salesforce header turned off, the developer gains a lot of freedom in laying out the page as desired. But this comes at the cost of some standard features of that layout, such as the sidebar. Forsaking the Salesforce layout means that the Salesforce runtime wouldn’t know where to put the sidebar, and Salesforce has never released a “Sidebar component” like they have with the Chatter component.

So, in short, Jack is correct… if you turn off the Salesforce header, you lose the sidebar and all the declarative features that go with it. You’d have to create a new sidebar from scratch (more or less) using whatever metadata you have access to.