The only problem is that it is also adding space between headings (section, subsection, etc.)

How can I avoid that?
Thanks in advance

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[url=http://ctan.org/pkg/parskip]parskip[/url] manual wrote: […] This package is no more than quick fix; the ‘proper’ way to achieve effects as far-reaching as this is to create a new class. An example class is to be found in the ntgclass set: »artikel3.cls«
The koma-script bundle classes and the memoir class all provide similar functionality, and their respective documentation files discuss the pros (such as they are) and cons of this approach.
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