By default, any filter from any tab will be applied globally to the entire dashboard.
To change this behavior, click on the menu icon of the tab you wish to modify.
In the Tab Detail page, you can choose either
1) Merge with current query or
2) Override the current query
Merge will create a "base filter" for that tab which will always be applied. Any additional filters will be applied on top of the base filter.
Override will ignore any filters not specified in the Tab Detail page when setting up the query, effectively disabling any interaction with the tab.