My Log Window disappeared and it is no longer possible to find it anywhere on the screen. This happened after I changed my Main Display to another display. Turning it on/off in the Window->Log menu does not bring it back and I see no options to toggle it and to move/expand it to find it.
Find the one that has a reference to the "Log window" (in my systems it is the Pane-11). Delete this key (do this operation while no Amibroker instance is running - eventually klll any existing Broker.exe instance using the TaskManager before opening the registry editor).
Close the registry editor and launch AmiBroker; it will reset the Log Window position to its default position (turn it on/off to see it).
@trongart, if you frequently use _TRACE() / _TRACEF() it may be useful to install an external (system) debug viewer like it was discussed in this other thread.