parameters: the textpick picker is a button nested in the box's recess

The completion picker moves from a sliver beside the TextBox to a raised
BUTTON (with_raised) sitting inside the right end of the box's recessed
well; the box spans the full row again, and the button places itself below
the detached label band, inset within the well.

The picker also acts on PRESSES only now, swallowing the release over the
button: releases used to reach the dropdown, and one arriving before the
open animation's first frame (a fast or injected click) read as an outside
press and closed the menu it had just opened — an open-then-instantly-
closed race the old sliver layout masked.

 src/widget/container/parameters_bg.rs | 71 ++++++++++++++++++++++++-----------
 1 file changed, 50 insertions(+), 21 deletions(-)

diff --git a/src/widget/container/parameters_bg.rs b/src/widget/container/parameters_bg.rs
index f14efc6..1c897f3 100644
--- a/src/widget/container/parameters_bg.rs
+++ b/src/widget/container/parameters_bg.rs
@@ -39,8 +39,9 @@ fn is_text_row(t: &str) -> bool {
     t == "text" || t.starts_with("textpick")
 }
 
-/// Width of a textpick row's picker trigger, carved off the TextBox's right.
-const PICK_W: f32 = 26.0;
+/// Width of a textpick row's picker button, nested inside the right end of
+/// the TextBox's recessed well.
+const PICK_W: f32 = 24.0;
 
 pub struct ParametersBg {
     rect: Rect,
@@ -600,8 +601,19 @@ impl ParametersBg {
             if let Some(d) = d_opt {
                 let r = rects[i];
                 if self.display_params[i].2.starts_with("textpick") {
-                    // The picker trigger: a sliver at the text box's right.
-                    d.set_rect(r.0 + r.2 - PICK_W, r.1, PICK_W, r.3);
+                    // The picker button nests INSIDE the text box's recessed
+                    // well (the box spans the full row): below the detached
+                    // label band, inset from the well's right edge.
+                    let label_top = if crate::layout::control_label_layout() == "side" {
+                        0.0
+                    } else {
+                        crate::layout::control_label_font_detached_parsed().1
+                            + crate::layout::control_label_margin()
+                    };
+                    let inset = 3.0;
+                    let by = r.1 + label_top + inset;
+                    let bh = (r.3 - label_top - 2.0 * inset).max(8.0);
+                    d.set_rect(r.0 + r.2 - PICK_W - inset - 2.0, by, PICK_W, bh);
                 } else {
                     d.set_rect(r.0, r.1, r.2, r.3);
                 }
@@ -610,11 +622,7 @@ impl ParametersBg {
         for (i, tb_opt) in self.texts.iter_mut().enumerate() {
             if let Some(tb) = tb_opt {
                 let r = rects[i];
-                if self.display_params[i].2.starts_with("textpick") && self.choices[i].is_some() {
-                    tb.set_rect(r.0, r.1, r.2 - PICK_W - 4.0, r.3);
-                } else {
-                    tb.set_rect(r.0, r.1, r.2, r.3);
-                }
+                tb.set_rect(r.0, r.1, r.2, r.3);
             }
         }
         for (i, cb_opt) in self.toggles.iter_mut().enumerate() {
@@ -1917,16 +1925,29 @@ impl Input for ParametersBg {
                         }
                     } else if is_text_row(&p.2) {
                         if let Some(d) = &mut self.choices[i] {
-                            if d.mouse_input(button, state, px, py, ui) {
-                                if d.take_change() {
-                                    if let Some(val) = d.get_value_string() {
-                                        if let Some(tb) = &mut self.texts[i] {
-                                            tb.text = val.clone();
-                                            tb.edit_buffer = val.clone();
+                            // The picker acts on PRESSES only; the release
+                            // over the button is swallowed. Releases used to
+                            // reach the dropdown, and one arriving before the
+                            // open animation's first frame (a fast or
+                            // injected click) read as an outside press and
+                            // closed the menu it had just opened.
+                            let (bx, by, bw, bh) = d.rect();
+                            let on_button =
+                                px >= bx && px <= bx + bw && py >= by && py <= by + bh;
+                            if state == ElementState::Pressed {
+                                if d.mouse_input(button, state, px, py, ui) {
+                                    if d.take_change() {
+                                        if let Some(val) = d.get_value_string() {
+                                            if let Some(tb) = &mut self.texts[i] {
+                                                tb.text = val.clone();
+                                                tb.edit_buffer = val.clone();
+                                            }
+                                            p.1 = val;
                                         }
-                                        p.1 = val;
                                     }
+                                    return true;
                                 }
+                            } else if on_button {
                                 return true;
                             }
                         }
@@ -2602,7 +2623,13 @@ impl ParamController for ParametersBg {
                     if options.is_empty() {
                         None
                     } else {
-                        Some(Dropdown::new(options, 0).with_custom_display_text("\u{25be}"))
+                        // A raised face: the picker reads as a BUTTON sitting
+                        // in the box's recess, not a bare glyph beside it.
+                        Some(
+                            Dropdown::new(options, 0)
+                                .with_custom_display_text("\u{25be}")
+                                .with_raised(true),
+                        )
                     }
                 } else {
                     None
@@ -2815,11 +2842,13 @@ mod tests {
         assert!(p.choices[1].is_none(), "plain text has no picker");
         assert!(p.texts[2].is_some() && p.choices[2].is_none(), "no options, no picker");
 
-        // Layout: the picker is a sliver at the box's right edge.
-        let (tx, _, tw, _) = p.texts[0].as_ref().unwrap().rect();
-        let (dx, _, dw, _) = p.choices[0].as_ref().unwrap().rect();
+        // Layout: the box spans the full row; the picker button nests
+        // inside it (within the box's right end).
+        let (tx, ty, tw, th) = p.texts[0].as_ref().unwrap().rect();
+        let (dx, dy, dw, dh) = p.choices[0].as_ref().unwrap().rect();
         assert_eq!(dw, PICK_W);
-        assert!(dx >= tx + tw, "picker sits right of the text box");
+        assert!(dx > tx && dx + dw < tx + tw, "button inside the box horizontally");
+        assert!(dy > ty && dy + dh <= ty + th, "button inside the box vertically");
 
         // Both text variants lay out at the same row height.
         assert_eq!(p.inner().row_height(0), p.inner().row_height(1));