float the selection panel over the game world instead of a side column

src/ui/BuildButtonBar.cpp

@@ -192,7 +192,7 @@ BuildButtonBar::BuildButtonBar(Simulation* sim, const GameConfig* config,
     // The bar floats over the rendered world rather than sitting in a panel, so it
     // brings its own opaque background to stay legible over any world content
     // (REQ-UI-BUILD-BAR). Palette colors keep it consistent with the buttons it holds
-    // and with the side panels; this is widget chrome, not world rendering, so it is
+    // and with the selection panel; this is widget chrome, not world rendering, so it is
     // deliberately not a visuals.toml color.
     setAttribute(Qt::WA_StyledBackground, true);
     setStyleSheet(QStringLiteral(
@@ -310,6 +310,11 @@ void BuildButtonBar::anchorTo(const QRect& worldViewRect)
     recenter();
 }
 
+int BuildButtonBar::getStripHeightPx() const
+{
+    return height() + kBottomMarginPx;
+}
+
 void BuildButtonBar::clearActiveButton()
 {
     if (m_activeIndex)