As the other candidates drop out, their support shifts within the non-Trump sector, more than it shifts to Trump.>
Jibberish. The shifts took place based on the strength of performances by each candidate. Trump actually gained a point on a mixed, probably overall neutral performance.
The larger shifts went from Walker, Bush and Cristie, and several who lost 1%. Walker, Bush and Cristie gave lackluster performances. All shifts track the perceived strength of performance with Cruz, Carson and Fiorina being the big gainers.
If the debate had been professionally done and the questions about critical issues for everyone, Trump might well have gained several points but he was too much under attack to shine very much in that debate.
And this is still one poll with a fairly high margin of error.
Not these shifts, in an online poll. They mean nothing. The coming shifts as people drop out.