The selector area of the dragging to select automatically goes all the way to the left; could that be changed so that the area shows up only from where the user clicked to where the cursor goes, like Windows Explorer? (see attached image)
The requested feature is showcased in the Cell Selection demo.
Yes, you can customize the color of the selection via the following CSS class:
.rgCellSelectorArea {
background-color: red !important;
}