Why did Salman Khan refused to shoot with Shahid Kapoor?

‘Phata Poster Nikal Hero’ has Salman Khan in a cameo that is being promoted as the highlight of the movie but it has been revealed that the two Salman Khan and Shahid Kapoor have not shot together for the scene.

In the scene, Salman is seen resting at the back seat of his SUV when Shahid and Ileana D’Cruz, who are chasing kidnappers on a scooter, happen to bump into Salman. Shahid’s character Vishwas Rao, a Salman fan, is happy to see his favourite actor and starts talking to him while riding his scooter.

As per sources ,“Salman bhai was not comfortable doing the cameo scene on the streets of Mumbai, hence the crew opted for a croma sequence inside a studio.If you observe closely, on the screen you will find Salman peeping out of the SUV window larger than life comparatively Shahid and Ileana on scooter look too minuscule. This only happens when the VFX supervisor can’t match the ratios of both the (Salman and Shahid-Ileana) layers together”
This was completely denied by the film unit .whatever is the truth, but Salman Khan and Shahid Kapoor fans are quite happy to see their favorites together.