There is a buzz among at least a few discussion boards/gathering places of Trump volunteers that he is going to go in for one of his crazy schemes to ruin the Dem Convention for Hillary, I've been told by a person I have reason to believe. They said they are messaging several other publicly pro-Sanders journalists and bloggers.

Speculation is that he will release some form of presidential election reform proposal involving some of kind preference voting. He may also demand that Gary Johnson be allowed to debate in the presidential debates. While there is no firm consensus on when the announcement is likely aside from "before October" there is some feeling Trump may announce during the Dem convention after Bernie has already given his speech. He may suggest he will run as an independent in his second term if Republican legislators can push his proposal through.

The major rules for presidential elections are enumerated in the Constitution and in the 12th Amendment.

Such a move by Trump is believed by his volunteers to have the potential to turn this election into a landslide victory for him in combination with other soon to be forthcoming messaging changes to improve his odds in swing states. Supposedly it will smooth over some his drama with Cruz and Kasich and other Republicans who claim he hijacked "their" party and is intended to garner the support of Gary Johnson's potential supporters as well as disgruntled Republican and Independent Sanders voters.

Trump has mad several more mediocre appeals to Sanders voters over the past week including at his convention.

Also its likely that if Trump does announce during the Dem convention he will steal the media thunder and attention from what is supposed to be Hillary's big week. This may attenuate or eliminate any convention bounce she receives.

If Trump was to take this position its believed Hillary would have to counter with her own, likely more restrained, proposal which can be spun as a flip flop and evidence that Trump is the leader and she is the reactive follower.

There is no detailed information on the precise messaging Trump would use following this proposal and I don't feel informed enough to speculate.