[LyX/master] Preventive fix inspired from ~

[Guillaume Munch]

commit 22edb3df96e78cf10aa94e0f2d9f6f6697534786
Author: Guillaume Munch <g...@lyx.org>
Date:   Fri Mar 10 23:20:29 2017 +0100

    Preventive fix inspired from ~
---
 src/TextMetrics.cpp |   27 ++++++++++++++++-----------
 1 files changed, 16 insertions(+), 11 deletions(-)

diff --git a/src/TextMetrics.cpp b/src/TextMetrics.cpp
index 5873a28..3dd0520 100644
--- a/src/TextMetrics.cpp
+++ b/src/TextMetrics.cpp
@@ -1361,18 +1361,23 @@ Inset * TextMetrics::editXY(Cursor & cur, int x, int y,
        if (edited == inset && cur.pos() == it->pos) {
                // non-editable inset, set cursor after the inset if x is
                // nearer to that position (bug 9628)
+               // TODO: This should be replaced with an improvement of
+               // Cursor::moveToClosestEdge that handles rtl text. (Which 
could not
+               // be tested because of #10569.)
                CoordCache::Insets const & insetCache = 
bv_->coordCache().getInsets();
-               Dimension const & dim = insetCache.dim(inset);
-               Point p = insetCache.xy(inset);
-               bool const is_rtl = text_->isRTL(text_->getPar(pit));
-               if (is_rtl) {
-                       // "in front of" == "right of"
-                       if (abs(p.x_ - x) < abs(p.x_ + dim.wid - x))
-                               cur.posForward();
-               } else {
-                       // "in front of" == "left of"
-                       if (abs(p.x_ + dim.wid - x) < abs(p.x_ - x))
-                               cur.posForward();
+               if (insetCache.has(inset)) {
+                       Dimension const & dim = insetCache.dim(inset);
+                       Point p = insetCache.xy(inset);
+                       bool const is_rtl = text_->isRTL(text_->getPar(pit));
+                       if (is_rtl) {
+                               // "in front of" == "right of"
+                               if (abs(p.x_ - x) < abs(p.x_ + dim.wid - x))
+                                       cur.posForward();
+                       } else {
+                               // "in front of" == "left of"
+                               if (abs(p.x_ + dim.wid - x) < abs(p.x_ - x))
+                                       cur.posForward();
+                       }
                }
        }