From 7177fd593673bf77bdb689a1fb97d9b35f8d958d Mon Sep 17 00:00:00 2001
From: Dmitry Batrak <Dmitry.Batrak@jetbrains.com>
Date: Mon, 24 Mar 2014 11:39:51 +0400
Subject: [PATCH] IDEA-120730 Editor drops the existing selection when hitting
 Alt while selecting

---
 .../openapi/editor/impl/EditorImpl.java       |  4 ++++
 .../openapi/editor/EditorMultiCaretTest.java  | 21 +++++++++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/platform/platform-impl/src/com/intellij/openapi/editor/impl/EditorImpl.java b/platform/platform-impl/src/com/intellij/openapi/editor/impl/EditorImpl.java
index 85f381c969cc..c90c5286debb 100644
--- a/platform/platform-impl/src/com/intellij/openapi/editor/impl/EditorImpl.java
+++ b/platform/platform-impl/src/com/intellij/openapi/editor/impl/EditorImpl.java
@@ -4270,6 +4270,10 @@ public final class EditorImpl extends UserDataHolderBase implements EditorEx, Hi
           }
 
           if (!myMousePressedInsideSelection) {
+            if (myCaretModel.supportsMultipleCarets()) {
+              oldSelectionStart = logicalPositionToOffset(myLastMousePressedLocation);
+              oldVisLeadSelectionStart = logicalToVisualPosition(myLastMousePressedLocation);
+            }
             // There is a possible case that lead selection position should be adjusted in accordance with the mouse move direction.
             // E.g. consider situation when user selects the whole line by clicking at 'line numbers' area. 'Line end' is considered
             // to be lead selection point then. However, when mouse is dragged down we want to consider 'line start' to be
diff --git a/platform/platform-tests/testSrc/com/intellij/openapi/editor/EditorMultiCaretTest.java b/platform/platform-tests/testSrc/com/intellij/openapi/editor/EditorMultiCaretTest.java
index 6f37735002a0..caec0af4de9c 100644
--- a/platform/platform-tests/testSrc/com/intellij/openapi/editor/EditorMultiCaretTest.java
+++ b/platform/platform-tests/testSrc/com/intellij/openapi/editor/EditorMultiCaretTest.java
@@ -160,6 +160,27 @@ public class EditorMultiCaretTest extends AbstractEditorTest {
                       "line");
   }
 
+  public void testAltOnOffWhileDragging() throws Exception {
+    init("line1\n" +
+         "line2\n" +
+         "line3",
+         TestFileType.TEXT);
+    setEditorVisibleSize(1000, 1000);
+
+    mouse().clickAt(0, 1).dragTo(1, 2);
+    checkResultByText("l<selection>ine1\n" +
+                      "li<caret></selection>ne2\n" +
+                      "line3");
+    mouse().alt().dragTo(1, 3);
+    checkResultByText("l<selection>in<caret></selection>e1\n" +
+                      "l<selection>in<caret></selection>e2\n" +
+                      "line3");
+    mouse().dragTo(2, 4).release();
+    checkResultByText("l<selection>ine1\n" +
+                      "line2\n" +
+                      "line<caret></selection>3");
+  }
+
   public void testTyping() throws Exception {
     init("some<caret> text<caret>\n" +
          "some <selection><caret>other</selection> <selection>text<caret></selection>\n" +