Fix crash if log window is open when entering mission.

Use signal to append text to LogWindow to avoid crash from crossing thread boundaries.
Change modal flag to enable interacting with LogWindow while the mission is running

Fixes https://github.com/dcs-liberation/dcs_liberation/issues/1493

qt_ui/windows/logs/QLogsWindow.py

@@ -1,18 +1,21 @@
 import logging
 import typing
 
+from PySide2.QtCore import Signal
 from PySide2.QtWidgets import (
     QDialog,
     QPlainTextEdit,
     QVBoxLayout,
     QPushButton,
 )
-from PySide2.QtGui import QTextCursor
+from PySide2.QtGui import QTextCursor, QIcon
 
 from qt_ui.logging_handler import HookableInMemoryHandler
 
 
 class QLogsWindow(QDialog):
+    appendLogSignal = Signal(str)
+
     vbox: QVBoxLayout
     textbox: QPlainTextEdit
     clear_button: QPushButton
@@ -24,6 +27,7 @@ class QLogsWindow(QDialog):
         self.setWindowTitle("Logs")
         self.setMinimumSize(400, 100)
         self.resize(1000, 450)
+        self.setWindowIcon(QIcon("./resources/icon.png"))
 
         self.vbox = QVBoxLayout()
         self.setLayout(self.vbox)
@@ -44,6 +48,8 @@ class QLogsWindow(QDialog):
         self.clear_button.clicked.connect(self.clearLogs)
         self.vbox.addWidget(self.clear_button)
 
+        self.appendLogSignal.connect(self.appendLog)
+
         self._logging_handler = None
         logger = logging.getLogger()
         for handler in logger.handlers:
@@ -53,7 +59,10 @@ class QLogsWindow(QDialog):
         if self._logging_handler is not None:
             self.textbox.setPlainText(self._logging_handler.log)
             self.textbox.moveCursor(QTextCursor.End)
-            self._logging_handler.setHook(self.appendLog)
+            # The Handler might be called from a different thread,
+            # so use signal/slot to properly handle the event in the main thread.
+            # https://github.com/dcs-liberation/dcs_liberation/issues/1493
+            self._logging_handler.setHook(self.appendLogSignal.emit)
         else:
             self.textbox.setPlainText("WARNING: logging not initialized!")