diff --git a/qt/lc_qpreferencesdialog.cpp b/qt/lc_qpreferencesdialog.cpp
index d7e3960f..da3a2574 100644
--- a/qt/lc_qpreferencesdialog.cpp
+++ b/qt/lc_qpreferencesdialog.cpp
@@ -674,6 +674,18 @@ void lcQPreferencesDialog::on_mouseAssign_clicked()
 			Modifiers |= Qt::AltModifier;
 	}
 
+	for (int ToolIdx = 0; ToolIdx < LC_NUM_TOOLS; ToolIdx++)
+	{
+		if (ToolIdx != ButtonIndex && options->MouseShortcuts.mShortcuts[ToolIdx].Button == Button && options->MouseShortcuts.mShortcuts[ToolIdx].Modifiers == Modifiers)
+		{
+			if (QMessageBox::question(this, tr("Override Shortcut"), tr("This shortcut is already assigned to '%1', do you want to replace it?").arg(gToolNames[ToolIdx]), QMessageBox::Yes | QMessageBox::No) == QMessageBox::No)
+				return;
+
+			options->MouseShortcuts.mShortcuts[ToolIdx].Button = Qt::NoButton;
+			options->MouseShortcuts.mShortcuts[ToolIdx].Modifiers = Qt::NoModifier;
+		}
+	}
+
 	int ItemIndex = ui->mouseTree->indexOfTopLevelItem(Current);
 	options->MouseShortcuts.mShortcuts[ItemIndex].Button = Button;
 	options->MouseShortcuts.mShortcuts[ItemIndex].Modifiers = Modifiers;