By clicking the Current tab, you can see a call stack (if available) that is closest to the current selection point in the timeline if a CPU thread segment is selected. In this case, the selection point is represented by a black arrow, or caret, above the timeline. When a blocking segment is selected, the caret is not displayed because there was no execution. However, the segment is still highlighted and a call stack is displayed.
The Current tab also displays information about DirectX activity segments, markers, and I/O access. For DirectX activity segments, information about the way DMA packets are processed by the hardware queue is displayed. For markers, information about the description and marker type is displayed. For I/O access, information about the file and number of bytes read or written is displayed.