Fix DnD issues regarding data type text (#9347)

* First dragged data should not contain new line character at the beginning
* Return any of "text", "Text" or "text/plain" in the method of getDataTransferText()
* Set only data of type "text" for IE on dragstart
* Clarify return of getDataTransferText() method
* Ignore generated data that is null

1 files changed, 13 insertions, 0 deletions

diff --git a/shared/src/main/java/com/vaadin/shared/ui/dnd/DragSourceState.java b/shared/src/main/java/com/vaadin/shared/ui/dnd/DragSourceState.java
index 66323a91c6..0fefd05665 100644
--- a/shared/src/main/java/com/vaadin/shared/ui/dnd/DragSourceState.java
+++ b/shared/src/main/java/com/vaadin/shared/ui/dnd/DragSourceState.java
@@ -45,6 +45,19 @@ public class DragSourceState extends SharedState {
      */
     public static final String DATA_TYPE_TEXT = "text";
 
+    /**
+     * Data type {@code "Text"}. IE 11 stores data dragged from the desktop as
+     * "Text" with capital letter.
+     */
+    public static final String DATA_TYPE_TEXT_IE = "Text";
+
+    /**
+     * Data type {@code "text/plain"} for reading data from {@code DataTransfer}
+     * object. Some browsers convert store data with {@code "text"} as {@code
+     * "text/plain"} when transferring data.
+     */
+    public static final String DATA_TYPE_TEXT_PLAIN = "text/plain";
+
     public static final String RESOURCE_DRAG_IMAGE = "drag-image";
 
     /**