patch 8.1.1866: modeless selection in GUI does not work properly

Problem:    Modeless selection in GUI does not work properly.
Solution:   Avoid going beyond the end of the line. (closes #4783)
diff --git a/src/ui.c b/src/ui.c
index 1b1b2cd..3f52db1 100644
--- a/src/ui.c
+++ b/src/ui.c
@@ -1619,12 +1619,12 @@
 
 	if (row == row2)
 	    end_col = col2;
-	else
 #ifdef FEAT_TEXT_PROP
+	else if (clip_star.max_col < Columns)
 	    end_col = clip_star.max_col + 1;
-#else
-	    end_col = Columns;
 #endif
+	else
+	    end_col = Columns;
 
 	line_end_col = clip_get_line_end(&clip_star, row);
 
@@ -1797,7 +1797,7 @@
 	return 0;
     for (i =
 #ifdef FEAT_TEXT_PROP
-	    cbd->max_col + 1;
+	    cbd->max_col >= screen_Columns ? screen_Columns : cbd->max_col + 1;
 #else
 	    screen_Columns;
 #endif
diff --git a/src/version.c b/src/version.c
index f8a907e..4b3637c 100644
--- a/src/version.c
+++ b/src/version.c
@@ -770,6 +770,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1866,
+/**/
     1865,
 /**/
     1864,