Issue with U2715H daisy chaining

I have the following system:

Windows 7 64-bit

Geforce GTX780

HP LP3065

2 x Dell U2715H

I have the HP in the middle, being the main monitor (setting in Windows), surrounded by the Dell's in portrait mode. Both Dell's have the "Daisy Chain 1.2" enabled. The right Dell is the one connected to computer, using the mini displayport cable that came with the monitor. The left Dell is connected to the right one, making use of daisy chaining, again using the mini display port cable that came with the monitor.

When all three monitors are on and I turn off the left Dell it makes the right Dell the main monitor for some reason. I do not know if this is a Windows issue, a Dell issue, or just "daisy" issue. It is uber annoying since it means I kind of cannot turn the left Dell off to work with just the HP and the right Dell (cannot turn off the right instead of the left either since turning of the right will effectively shut down the left). Sure, when I turn off the right one as well it reverts back the HP to being the main, but again, I sometimes want to use the HP only, sometimes the HP + one Dell, sometimes all three of them. The latter will causes headaches when switching back to only using two.

Any solution(s) to this issue?

On a side note, before I enabled "Daisy chaining 1.2" on the left Dell I got blue screened when turning on the right Dell. The problem is, you are not abled to enable daisy chaining on the left monitor BEFORE it gets a signal from the right one, meaning I had to endure one blue screen, reboot, and then enable it. Weird stuff, but at least I do not get any more blue screens now (knock on wood).