When watching live image updates, for example when slicing though a stack of images, it is often useful if the colour scale does not automatically recalculate the scale based on the image data, especially when one wishes monitor a change in intensity. The Colour mapping tool in DAWN has an action to set "Histogram range locked for this image" in the view menu and on the toolbar. Checking this action means the current colour scale will be applied to all future plotted images, regardless of the range of the data.
As a note, with the colour scale locked the image update rate should be significantly faster, since the range does not need to be calculated for each image and this process can be expensive especially when using the Outlier Values Type.