Preserve Brush Settings While Switching Among Brush Tip Presets

Click on any of the lock icons to the right of each of the Brush panel’s panes to preserve the settings in that pane when you switch to another brush tip preset. For example, clicking on the lock to the right of Shape Dynamics, will allow you to retain those settings even if you switch to a totally different brush tip. Any unlocked panes will switch to the new brush tip’s default settings.

Photoshop Brush Panel