Step 1:
Download the windowLevelMacro.jar Here and place this in your
ImageJ/plugins folder. On Windows this is typically C:\Program Files\ImageJ\plugins
Note: On Windows Internet Explorer will sometimes rename windowLevelMacro.jar to windowLevelMacro.zip.
If you experience problems please confirm that windowLevelMacro.jar is present in the ImageJ/plugins directory.
Step 2:
Add the following text to the beginning of your ImageJ/macros/StartupMacros.txt file:
macro "Adjust Window Level Tool - T0910W T9910L"{}
macro "Adjust Window Level Tool Selected"{call('edu.ucla.alger.wlmacro.WindowLevelMacro.initialize');}
Step 3:
Restart/Start ImageJ