I added a variable to text is input just in case you are recycling the object.
+ Text: Is Input
----+ Keyboard: On any key pressed
-----> Text: Append Keyboard.TypedKey
--------+ Keyboard: ⇧ is down
--------+ System: right(Text.Text,5) = "Shift" //This is a compare event
---------> Text: Set text to left(Text.Text,len(Text.Text)-5)
--------+ Keyboard: Backspace is down
---------> Text: Set text to left(Text.Text,len(Text.Text)-1)
--------+ Keyboard: Space is down
---------> Text: Append " "