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The Collapse/Expand button within tracks can be very useful, so this is set to on by default. However, the small + button in each track can look odd in pictures, or some users may not like it. Unchecking this option will remove the button from the tracks. The button can be seen below.
Autochange View for BAM/SAM
This will change the view of your short read files from stacked reads to a depth graph when zoomed out to a certain level. More details about this function can be found under View Mode.
Reset all preferences to defaults
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