Stack trace files could be imported by selecting "Import stack trace ..."
from the "new" context menu entry of a sequence diagram.

The supported stack trace formats could be generated by
1. copy and paste of the output of gdb 'bt' command into a file
   (single line for each stack frame)

2. select frames in qtcreator stack window, right click and select
   "copy into clipboard", then paste into file

Examples of supported gdb stack trace formats are added to test/import/stack-trace

BUG:358867
FIXED-IN: 2.18.80 (KDE Applications 16.03.80)