For any of the text input fields, we can use ${<variable_name>} expression to use the global variable defined for each test plan. However, for anything else such as checkbox parameters, this is impossible unless you open .jmx file in a text editor and batch edit the entries. This feature would be very useful. For example, I might want to turn on/off Keep-Alive feature.
Definitely a pain, but not a bug.
this bug is 12 years old and should be closed as wontfix
This issue has been migrated to GitHub: https://github.com/apache/jmeter/issues/1252