Windows 7 64 bit
Dual Benq 24inch monitors
I noticed that Sigil v0.5.906 always launches on my primary monitor and refuses to launch on my secondary monitor where I want it. The older version of Sigil always opened at the last position it was when closed down.
I have found a solution (of sorts).
Sigil will refuse to open on the secondary monitor if its window was maximised when it was last closed.
So, I clicked on the middle button in the top right-hand corner to reduce its size, then dragged the sides and top so that it was nearly maximised. Then I dragged it to my secondary monitor. This gives me plenty of space to work and Sigil now always launches where I want it to.