From 57fc939e22cc5f2155da6a941b3410c4a81e48b9 Mon Sep 17 00:00:00 2001
From: BDisp <bd.bdisp@gmail.com>
Date: Thu, 21 Jul 2022 13:55:51 +0100
Subject: [PATCH] Fixes #1866. Bug when scrolling text and type in a TextView.
 (#1868)

---
 Terminal.Gui/Views/TextView.cs |  2 +-
 UnitTests/TextViewTests.cs     | 20 ++++++++++++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/Terminal.Gui/Views/TextView.cs b/Terminal.Gui/Views/TextView.cs
index 66bca7fb4..bfaad7f38 100644
--- a/Terminal.Gui/Views/TextView.cs
+++ b/Terminal.Gui/Views/TextView.cs
@@ -2384,7 +2384,7 @@ namespace Terminal.Gui {
 			}
 			var prow = currentRow - topRow;
 			if (!wrapNeeded) {
-				SetNeedsDisplay (new Rect (0, prow, Frame.Width, prow + 1));
+				SetNeedsDisplay (new Rect (0, prow, Math.Max (Frame.Width, 0), Math.Max (prow + 1, 0)));
 			}
 		}
 
diff --git a/UnitTests/TextViewTests.cs b/UnitTests/TextViewTests.cs
index ba00845b3..5584e66bb 100644
--- a/UnitTests/TextViewTests.cs
+++ b/UnitTests/TextViewTests.cs
@@ -5707,5 +5707,25 @@ line.
 			});
 			Assert.Null (exception);
 		}
+
+		[Fact]
+		[AutoInitShutdown]
+		public void ScrollDownTillCaretOffscreen_ThenType ()
+		{
+			var tv = new TextView {
+				Width = 10,
+				Height = 5
+			};
+
+			// add 100 lines of wide text to view
+			for (int i = 0; i < 100; i++)
+				tv.Text += new string ('x', 100) + Environment.NewLine;
+
+			Assert.Equal (0, tv.CursorPosition.Y);
+			tv.ScrollTo (50);
+			Assert.Equal (0, tv.CursorPosition.Y);
+
+			tv.ProcessKey (new KeyEvent (Key.p, new KeyModifiers ()));
+		}
 	}
 }
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