Hi Pieter
Ignore MrT, he must be an idiot!
Don't stress too much about your little one, this is very typical behaviour of a 4 year old. They do tend to live in a fantasy world much of the time and their perception of past events (as recent as 5 minutes ago even!) can often be a little skewed.
Just be patient with her and stand your ground, she is also testing her boundaries with you. When she does lie, make sure that she understands that it is wrong to tell untruths. Perhaps you could look for a book on the topic of lying that you can read to her - something fictional and age appropriate that will appeal to her.
If this kind of behaviour continues after around the age of 6, you may want to seek some professional guidance; but for now be reassured in the fact that this is fairly normal for her age group albeit annoying.
My step-daughter once told her mom that my husband had hit her on the back with a wooden spoon and we didn't even own a wooden spoon at the time! Her older sister also told their mom that my hubby had been drinking beer and puking all day while she was with him and this was nonsense. They were both around the age of 4 at the time.
Best of luck!