THE WISHLIST WE’RE ALL DREAMING ABOUT BUT MAY NEVER SEE:
Variable Filter: Easily zap those unnecessary variables. (No brainer)
Global Variables: Handy variables available across the entire workflow without the need for a node connection. So, Really floating.
Floating Statistics Window: Detachable window that auto-updates to show the selected node’s stats. Super handy in the new UI!
Different UI Modes: Dark mode, Retro mode, Creme mode, Ice Cream mode, Vegan mode. 
There are already “Workflow Variables” that do that. Though they seem to be considered ‘legacy’ now.
Yes Markus @mlauber71. I found it totally handy. I remember this discussion. Perhaps it wont be bad idea to make a new easy version of global floating variables. Is there the feature of global floating variables still available in KNIME 5.1+? I couldn’t find it.
You have to switch to the old GUI in order to use it …
Variable Filter will be present in V 5.3!
@VAGR_ISK when you are in the new „Modern UI“ click preferences in the top right and select the menu option about „Classic UI“.
About workflow variable management, you might find the read / write variable nodes from @Vernalis more than helpful 
@mwiegand Thanks it looks super handy. Will try 4 sure.
Following on from @iCFO’s comment…
You can also create your own global constants by adding entries in the knime.ini file, as shown in this post
(And thanks - again! - to @mwiegand for more free publicity!)
Steve