The purpose of the Draw Settings Pane (Tab) is to provide access to the various settings that control how a DrawStyle is displayed in the Viewport. Many of the settings found in this pane were previously located in the Tool Settings pane but have since been extracted into their own pane to better support a growing number of options for some of the more complex DrawStyles, such as NVIDIA Iray.
This pane provides an option to change the drawstyle for the active viewport (whichever one is currently highlighted). Note that it is possible to have multiple viewports displayed at the same time and that each can have a different DrawStyle applied. When clicking between different viewports, the settings displayed in this pane will change to correspond with the DrawStyle applied to the selected viewport.
Note that the nvidia_iray DrawStyle uses a lot of memory, so setting multiple viewports to the NVIDIA Iray DrawStyle can significantly slow down Daz Studio and possibly lead to a crash due to a lack of available system resources.