Changed GetClosestMethod to find item with the nearest edge instead o…

[faeriedust]

…f the one with the nearest upper left corner. This fixes my use case in which the items were nested

[faeriedust]

Oh.. this won't work if the contents of the list item are larger than the outer list item... Though this situation is pretty weird lol

[faeriedust]

I guess ideal approach would be to just handle nested items directly, and not allow the inner ones?

[punker76]

@faeriedust Can you create an example for this? Would be much easier to debug and find a solution. Thx

[faeriedust]

I gave example in #181, though not coded out.
Not sure if I'll have to time to write out separated code from my project or not, probably not

[faeriedust]

Actually I will try

[faeriedust]

@punker76

https://github.com/faeriedust/GongWPFDemo

The master branch illustrates the bug when you try to move a job to below task F. (It won't let you.)
The GetClosestWithNestedItemsFix branch illustrates how my commit fixes it (though there are probably other ways of handling it as well.)

[punker76]

@faeriedust Thx for the sample to reproduce the issue, it helps me to find out what's going wrong! And this issue should be fixed with f877268

[punker76]

@faeriedust Oh yeah, I take your PR for #188 Big THX!

[faeriedust]

Glad it helped. :D