6 files changed, 34 insertions, 12 deletions
diff --git a/src/nvim/ex_cmds.c b/src/nvim/ex_cmds.c
index 45d08d40bc..82422a78c3 100644
--- a/src/nvim/ex_cmds.c
+++ b/src/nvim/ex_cmds.c
@@ -3651,6 +3651,13 @@ static int do_sub(exarg_T *eap, proftime_T timeout, long cmdpreview_ns, handle_T
     sub_needs_free = cmdpreview && sub != source;
   }
 
+  bool cmdheight0 = p_ch < 1 && !ui_has(kUIMessages);
+  if (cmdheight0) {
+    // If cmdheight is 0, cmdheight must be set to 1 when we enter command line.
+    set_option_value("ch", 1L, NULL, 0);
+    redraw_statuslines();
+  }
+
   // Check for a match on each line.
   // If preview: limit to max('cmdwinheight', viewport).
   linenr_T line2 = eap->line2;
@@ -4461,6 +4468,11 @@ skip:
     }
   }
 
+  if (cmdheight0) {
+    // Restore cmdheight
+    set_option_value("ch", 0L, NULL, 0);
+  }
+
   kv_destroy(preview_lines.subresults);
   return retv;
 #undef ADJUST_SUB_FIRSTLNUM
diff --git a/src/nvim/ex_getln.c b/src/nvim/ex_getln.c
index 01f16f3383..49f946d6c0 100644
--- a/src/nvim/ex_getln.c
+++ b/src/nvim/ex_getln.c
@@ -688,12 +688,12 @@ static void finish_incsearch_highlighting(int gotesc, incsearch_state_T *s, bool
 /// @param init_ccline  clear ccline first
 static uint8_t *command_line_enter(int firstc, long count, int indent, bool init_ccline)
 {
-  bool cmdheight0 = p_ch < 1 && !ui_has(kUIMessages) && vpeekc() == NUL;
+  bool cmdheight0 = p_ch < 1 && !ui_has(kUIMessages);
 
   if (cmdheight0) {
     // If cmdheight is 0, cmdheight must be set to 1 when we enter command line.
     set_option_value("ch", 1L, NULL, 0);
-    redraw_statuslines();
+    update_screen(VALID);                 // redraw the screen NOW
   }
 
   // can be invoked recursively, identify each level
@@ -985,6 +985,9 @@ theend:
   if (cmdheight0) {
     // Restore cmdheight
     set_option_value("ch", 0L, NULL, 0);
+
+    // Redraw is needed for command line completion
+    redraw_all_later(CLEAR);
   }
 
   return p;
diff --git a/src/nvim/message.c b/src/nvim/message.c
index 733b4808fe..0cd323c234 100644
--- a/src/nvim/message.c
+++ b/src/nvim/message.c
@@ -891,7 +891,7 @@ char_u *msg_may_trunc(bool force, char_u *s)
 
   room = (Rows - cmdline_row - 1) * Columns + sc_col - 1;
   if ((force || (shortmess(SHM_TRUNC) && !exmode_active))
-      && (int)STRLEN(s) - room > 0) {
+      && (int)STRLEN(s) - room > 0 && p_ch > 0) {
     int size = vim_strsize((char *)s);
 
     // There may be room anyway when there are multibyte chars.
@@ -3083,10 +3083,11 @@ void msg_clr_eos_force(void)
     msg_row = msg_grid_pos;
   }
 
-  grid_fill(&msg_grid_adj, msg_row, msg_row + 1, msg_startcol, msg_endcol,
-            ' ', ' ', HL_ATTR(HLF_MSG));
   if (p_ch > 0) {
-    grid_fill(&msg_grid_adj, msg_row + 1, Rows, 0, Columns, ' ', ' ', HL_ATTR(HLF_MSG));
+    grid_fill(&msg_grid_adj, msg_row, msg_row + 1, msg_startcol, msg_endcol,
+              ' ', ' ', HL_ATTR(HLF_MSG));
+    grid_fill(&msg_grid_adj, msg_row + 1, Rows, 0, Columns,
+              ' ', ' ', HL_ATTR(HLF_MSG));
   }
 
   redraw_cmdline = true;  // overwritten the command line
diff --git a/src/nvim/ops.c b/src/nvim/ops.c
index 42beb2e16d..639b7fd738 100644
--- a/src/nvim/ops.c
+++ b/src/nvim/ops.c
@@ -2791,7 +2791,7 @@ static void op_yank_reg(oparg_T *oap, bool message, yankreg_T *reg, bool append)
     xfree(reg->y_array);
   }
 
-  if (message) {  // Display message about yank?
+  if (message && (p_ch > 0 || ui_has(kUIMessages))) {  // Display message about yank?
     if (yank_type == kMTCharWise && yanklines == 1) {
       yanklines = 0;
     }
diff --git a/src/nvim/screen.c b/src/nvim/screen.c
index ea75900ded..bc11883fd8 100644
--- a/src/nvim/screen.c
+++ b/src/nvim/screen.c
@@ -6153,6 +6153,10 @@ void clearmode(void)
 
 static void recording_mode(int attr)
 {
+  if (p_ch <= 0 && !ui_has(kUIMessages)) {
+    return;
+  }
+
   msg_puts_attr(_("recording"), attr);
   if (!shortmess(SHM_RECORDING)) {
     char s[4];
@@ -6457,7 +6461,8 @@ int redrawing(void)
  */
 int messaging(void)
 {
-  return !(p_lz && char_avail() && !KeyTyped);
+  return !(p_lz && char_avail() && !KeyTyped)
+         && (p_ch > 0 || ui_has(kUIMessages));
 }
 
 /// Show current status info in ruler and various other places
@@ -6515,7 +6520,7 @@ static void win_redr_ruler(win_T *wp, bool always)
     }
   }
 
-  if (*p_ruf) {
+  if (*p_ruf && p_ch > 0 && !ui_has(kUIMessages)) {
     int save_called_emsg = called_emsg;
     called_emsg = false;
     win_redr_custom(wp, false, true);
diff --git a/src/nvim/window.c b/src/nvim/window.c
index 9b9a2126ff..9ac027d80f 100644
--- a/src/nvim/window.c
+++ b/src/nvim/window.c
@@ -5560,9 +5560,10 @@ static void frame_setheight(frame_T *curfrp, int height)
   if (curfrp->fr_parent == NULL) {
     // topframe: can only change the command line
     if (height > ROWS_AVAIL) {
-      // If height is greater than the available space, try to create space for the frame by
-      // reducing 'cmdheight' if possible, while making sure `cmdheight` doesn't go below 1.
-      height = MIN(ROWS_AVAIL + (p_ch - 1), height);
+      // If height is greater than the available space, try to create space for
+      // the frame by reducing 'cmdheight' if possible, while making sure
+      // `cmdheight` doesn't go below 1.
+      height = MIN((p_ch > 0 ? ROWS_AVAIL + (p_ch - 1) : ROWS_AVAIL), height);
     }
     if (height > 0) {
       frame_new_height(curfrp, height, false, false);