Stacking artefacts are the most common dark anomalies located at the edges of your image. Failing to deal with them will lead to a halo effect near the edges of your dataset.
'Un-glow Strength' throttles the strength of the effect.
As of 1.7, enhanced mouse controls are implemented; Zoom in.
Even the way StarTools displays and scales images, has been created specifically for astrophotography.
AutoDev will keep solving for a global strecth that best shows the detail in your RoI.
You can convert everything you see to a format you find convenient. Give it a try!