Dell monitor does not run on native resolution of 1600x900 pixel when connected to early macbook pro retina 2015 via thunderbolt just a few hours ago I got 2 dell E2015HV monitors, they are VGA monitors with a native resolution of 1600x900 pixel and since the macbook pro retina does not have any VGA ports I'm using two VGA to thunderbolt converters to connect the two displays to the computer to make them an extended display, but for some reason none of the displays want to run on their native resolution, and when I option + click on the scaled display setting from display preferences I see a list of custom resolutions but not one of them are the monitor's native resolution of 1600x900 pixel, as a matter of fact none of the resolutions listed in the list box even begin with the number 1600. So, the question now is that is there anything I can do to make them run on their native resolution? Thanks!
There is nothing wrong with your monitors, neither your Mac. That's a compatibility issue with your adapter. There are many comments on Amazon complaining about the same issue on similar converters. That seems, unfortunately, a hardware fault.

Example: http://www.amazon.com/gp/aw/cr/B00NH13I08/ref=mw_dp_cr