w2layout: add the 'load dynamic content' code so we can observe scroll bar show up / disappear + where exactly

cf. commit SHA-1: 9887059b81130195146837b24341ed94c49227b2:

* add the 'load dynamic content' code from layout example 4 to layout examples 8, 9 & 10 (layout with tabs, layout with toolbar, layout with titles) so that we can observe panel overflow behaviour (previously, overflow was applied to the entire panel, i.e. including the title, toolbar and tab-bar! This has been fixed in commit SHA-1: 33202a80a2f47d930af3cb317a8bcb55121c5675)