There has been herculean work to move to Bootstrap 3 and then 4 still some pages / interfaces / features were forgotten or have been partially upgraded.
This wiki page has been set to log and fix any leftovers where we can easily add and cross out.
Features
1.1.1. Wizards with Classic Bootstrap (fixed top bar) layout loose consistency in header
bg color lost, modules not centered, etc (at least)
To reproduce, apply in Site layout (in Control Panels > Look and Feel > General layout > Site layout): Classic Bootstrap (fixed top navbar).
then go to the Wizards: tiki-wizard_admin.php?stepNr=0&url=index.php , etc.
Example:
1.1.2. Tracker field type header not shown as tabs in PluginTracker
Since recently, according to some bug report by mikel finko (see item7162-Tracker-header-field-not-working) Tracker field type header is not shown anymore as tabs (even if set to be displayed as so, like in previous tiki versions) when using PluginTracker in a wiki page.
1.1.3. Pages