I tried the ValueHolder way and it kinda worked, but with some weird side effects:
First - the main view just remembered that it should be transparent, and as it was drawn on the screen, the main view background just disappeared and became a screen shot to whatever was below it on the desktop, albeit with a bit of scaling up. But when instruction <self barModel value: 'hello'> was commented out, this effect disappeared, and the view background returned to the default white. And when the <isTransparent> property was set to 'false' in 'View Composer', the effect disappeared also - fair game, as this should have been set to 'false' in the first place? But then, why only now?
Second - the Status Bar doesn't only show the string, in this case ( hello ), but it precedes it with the symbol ( 'U' ), which is Dolphin's class icon for UTF-encoded strings. And, after a few trials, it seems that whatever the displayed object is (Float, Integer, Point, etc.), it is always preceded by its class icon - not really the desired effect. I didn't find a fix for this yet!
What am I doing wrong?