Material-Custom node is corrupted on Copying / Duplicating if the code section contains a tab

When a material's Custom node contains a tab character, copying/duplicating the node will corrupt the code in the node.

1. In another program (notepad) press tab and copy the tab'ed space
2. Open UE4 Editor
3. Create new material in content browser
4. Add Custom node
5. Paste the tab
6. After the tab, enter int32 x=34;
7. Press enter to confirm the entry
8. Select the node and press Ctrl+C / Ctrl+V to copy/paste the node

Result:
New node shows "ntint32 x=34;"

Expected:
New node has the tabbed space followed by the variable declaration