Note that 28 USC §1400 is still in force; the Congress did not choose to remove the limits on patent case jurisdiction when it expanded other jurisdiction. It's right there in the US Code in black letters with no ambiguity.
But the notoriously corrupt patent appeals court -- the CAFC -- in its first decade of existence, abolished 28 USC §1400 by fiat.
The patent trolls went into business in East Texas soon after.
