diff --git a/src/nvim/insexpand.c b/src/nvim/insexpand.c
index 53c903d8d7..332e1c2261 100644
--- a/src/nvim/insexpand.c
+++ b/src/nvim/insexpand.c
@@ -5241,7 +5241,13 @@ void ins_compl_insert(bool move_cursor, bool insert_prefix)
 static void ins_compl_show_filename(void)
 {
   char *const lead = _("match in file");
-  int space = sc_col - vim_strsize(lead) - 2;
+
+  // In the case of ext_messages, `sc_col` is obsolete. Fortunately, long messages are no longer
+  // disruptive, so truncation could be skipped. But in this particular case, with default
+  // configuration `showmode cmdheight=1`, a multi-line message is shown partially, and a message
+  // that fits into one line is not shown at all. It's better to be consistent: it should not depend
+  // on the exact length of the message whether it is displayed at all.
+  int space = (ui_has(kUIMessages) ? Columns : sc_col) - vim_strsize(lead) - 2;
   if (space <= 0) {
     return;
   }
diff --git a/src/nvim/message.c b/src/nvim/message.c
index 684ccaeb25..d9f5111633 100644
--- a/src/nvim/message.c
+++ b/src/nvim/message.c
@@ -519,7 +519,12 @@ char *msg_strtrunc(const char *s, int force)
       room = (Rows - msg_row) * Columns - 1;
     } else {
       // Use up to 'showcmd' column.
-      room = (Rows - msg_row - 1) * Columns + sc_col - 1;
+      // In the case of ui2, we no longer need to avoid the "Press ENTER" prompt, but the message is
+      // still kept under 1 line to avoid glitches. For example, when a long search term is
+      // displayed that expands the cmdline, it will be immediately collapsed again when the search
+      // count is displayed, which leads to flickering on each hit.
+      int last_row = ui_has(kUIMessages) ? Columns : sc_col - 1;
+      room = (Rows - msg_row - 1) * Columns + last_row;
     }
     if (len > room && room > 0) {
       // may have up to 18 bytes per cell (6 per char, up to two