:::{index} Debug Windows; Call Stack
:::

# The Call Stack Window

The call stack window includes a list of active threads and displays the Python 
interpreter call stack while debugging. It shows the function name and the 
corresponding source code position for each stack frame. You can jump to a given 
code position by double-clicking on a stack frame line. 

The pinned  thread is the active "broken" thread and the pinned frame is the active 
frame of the active thread. You should note that the Call Stack window works in tandem 
with the  [Variables window](variableswindow), which displays the local and global variables 
for the selected (active)stack frame in this window. Initially the top stack frame is 
selected in the Call Stack window.  The [Watches  window](watcheswindow) evaluates 
watch expressions inside the active frame. Also commands you issue in the 
[Interpreter window](interpreter) and debugger hints (hovering the mouse on variable names
in the editor) are also evaluated inside the active frame. You can change the active thread 
and the active frame by selecting with the mouse a different one.

![graphic](images/callstackwindow1.JPG){width="41.3em" height="10em"}

**Debugger commands**

The Resume command (F9) resumes execution of all broken threads. All other debug commands (e.g. Step in, 
Step over, Step out) resume execution of the active thread only.


**Commands:**

Two commands  are provided to change the active stack frame using the keyboard and without 
having to switch view to the Call Stack Window.


*Previous Frame*\
Select previous (older) frame (default shortcut F11)

*Next Frame*\
Select next (newer) frame (default shortcut Shift+F11)

