did she leave the NPG? why? whas there a fight b-ween her + prince ?

In the accounts I've read it was problems with other band members attitudes that caused her to exit.

was it anything to do with Mayte joining ?

apparently rosie did not originally want to be in prince's band. she was interested in being a solo artist. but prince wanted her, so he convinced her to join the NPG, told her she would get a name for herself and then she could do her own album. stuff was recorded, i guess the album was titled, "concrete jungle." after the nude tour, and diamonds and pearls, her album still hadn't come out she had had enough waiting around on promises. prince released her from the band but her contract with him prohibited her from recording on her own for a few years. during this period she felt like prince was keeping her a slave, not letting her record on her own. he even removed her input to "the flow" when he revamped it for the symbol album. rosie's album "closer than close" finally dropped in early '95 and it featured limited involvement from prince (just "my tender heart" and a purple re-mix of "i want u").
yes, there was bad blood between rosie and prince for a short period. but they have long since reconciled. rosie attended prince and mayte's wedding in 1996 and she recorded songs for chaos and disorder and emancipation. rosie has commented on her frustration waiting around for her album to come out. she said it was hard to sit there and watch records by all these other acts come out while hers was still in the can. she even said, "i mean just because i wasn't sleeping with him, you know?"
by the way, all of this information is taken from memory of articles i read several years back. please forgive me if anything is inaccurate. i know some of it sounds sensational, but i guess that's what really went down. who do you suppose rosie was referring to when she said "just 'cause i wasn't sleeping with him..."? i can only think of carmen electra.