From f38483d441f465443253cd4ea51d35208e676b09 Mon Sep 17 00:00:00 2001
From: Vincent van Ravesteijn <vfr@lyx.org>
Date: Fri, 6 Nov 2009 18:08:06 +0000
Subject: [PATCH] branch: Fix bug #6237: The boundary has to be set correctly
 when moving up with a selection. If not, the cursor will remain on the same
 row when there are two e.g. displayed equations after each other. This will
 cause an infinite loop when SCREEN_UP is executed.

(I added a small extra safety measure to not change the logic resulting from r31864. I'm not sure it can harm.)

see r31863, r31864.

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/branches/BRANCH_1_6_X@31880 a592a061-630c-0410-9148-cb99ea01b6c8
---
 src/Cursor.cpp | 22 +++++++++++++++++-----
 status.16x     |  3 +++
 2 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/src/Cursor.cpp b/src/Cursor.cpp
index 0af4dde3c7..d68fef41d8 100644
--- a/src/Cursor.cpp
+++ b/src/Cursor.cpp
@@ -1859,31 +1859,43 @@ bool Cursor::upDownInText(bool up, bool & updateNeeded)
 			operator=(dummy);
 		}
 	} else {
-		// if there is a selection, we stay out of any inset, and just jump to the right position:
+		// if there is a selection, we stay out of any inset,
+		// and just jump to the right position:
 		Cursor old = *this;
+		int next_row = row;
+		bool update = false;
 		if (up) {
 			if (row > 0) {
-				top().pos() = min(tm.x2pos(pit(), row - 1, xo), top().lastpos());
+				--next_row;
+				update = true;
 			} else if (pit() > 0) {
 				--pit();
 				TextMetrics & tm = bv_->textMetrics(text());
 				if (!tm.contains(pit()))
 					tm.newParMetricsUp();
 				ParagraphMetrics const & pmcur = tm.parMetrics(pit());
-				top().pos() = min(tm.x2pos(pit(), pmcur.rows().size() - 1, xo), top().lastpos());
+				next_row = pmcur.rows().size() - 1;
+				update = true;
 			}
 		} else {
 			if (row + 1 < int(pm.rows().size())) {
-				top().pos() = min(tm.x2pos(pit(), row + 1, xo), top().lastpos());
+				++next_row;
+				update = true;
 			} else if (pit() + 1 < int(text()->paragraphs().size())) {
 				++pit();
 				TextMetrics & tm = bv_->textMetrics(text());
 				if (!tm.contains(pit()))
 					tm.newParMetricsDown();
-				top().pos() = min(tm.x2pos(pit(), 0, xo), top().lastpos());
+				next_row = 0;
+				update = true;
 			}
 		}
+		if (update) {
+			top().pos() = min(tm.x2pos(pit(), next_row, xo), top().lastpos());
 
+			boundary(tm.x2pos(pit(), next_row, xo)
+				== tm.x2pos(pit(), next_row, tm.width()));
+		}
 		updateNeeded |= bv().checkDepm(*this, old);
 	}
 
diff --git a/status.16x b/status.16x
index cf23b4f27d..a3a9cd3898 100644
--- a/status.16x
+++ b/status.16x
@@ -192,6 +192,9 @@ What's new
 
 - Fix a crash when leaving an empty superscript or subscript (bug 6193).
 
+- Fix an infinite loop when selecting multiple displayed equation right
+  after each other with LFUN_SCREEN_UP (bug 6237).
+
 - Fix a number of assertions when displaying error messages (bug 6205). 
 
 - Fix bad allocation exception when displaying long tooltips (bug 6215).