When creating a new fill layer within the layer docker ( + Layer > Fill Layer... ) , the new generator layer will start with it's color assigned for whatever the user has as their foreground color.
Workflow Improvement
I believe that this is a better alternative to always starting on black. Users can preemptively select or pick a color to use for their new fill layer.
KisDlgGeneratorLayer Woes
The current design of KisDlgGeneratorLayer makes it difficult to preemptively assign default values and is also prone to some bugs. For instance, going into the properties of a fill layer, switching to pattern, and then back to fill will lose whatever the users settings were when they entered the dialog. KisDlgGeneratorLayer Should probably keep a running configuration setup for every potential generator (initialized from the factory) until the dialog is closed. When closed, it should return the configuration of whichever generator was selected. This would make assigning default values easier and also reduce bug occurrence when poking around within the properties window. As it is right now, getting the "default configuration", changing the color property, and then resetting the configuration seemed to be the easiest way around this issue.