Blue tempo marker?

[Muxlow]

I did a search, but didn't find anything on this...

I just noticed that I have a blue tempo marker. When I drag it, rather than sliding across the timeline, it drags the entire timeline with it. The only thing special about it (aside from being blue) is that it's on the 1 bar, which I have set four bars into the timeline (so it goes -3, -2, -1, 0, 1, 2, 3, 4, etc.).

Any ideas how/why this works or how to control it? Can I make these blue markers anywhere in the timeline, or just this first bar?

[Slim Shady]

Go to your MIDI menu -> change tempo. You can add tempo changes anywhere you want in the song. Same goes for meter changes too.