I have created a layer of lat-long coordinates in the map I am working with that. On the map, I can appropriately size the "simple marker" representing each point for a given zoom. However, when I change the zoom or select a portion of the map to put into print composer, the size of the dots change. The size of the dots then seem to change again (seemingly randomly, though I assume there is some underlying logic that I am not understanding) as I export the print composition as an image. I would like the dots to keep the size of the dots consistent at different zoom levels, especially when exporting the image from the print composer.
In the "Layer Properties > Style" I have tried various combinations of units ("Map Unit", "Pixels", "Millimeters"), but cannot seem to find one that gives me a consistent size across different zooms and, especially, in the print composer and exported image. I have searched around the internet, but have not located anything specifically about this issue.
Is there a way to ensure that the dots representing the points stay a consistent size at different levels of zoom, especially in the print composer and in exported images?