--- scripts/ui/skill_window.gd
+++ scripts/ui/skill_window.gd
@@ -111,8 +111,18 @@ static func prereq_path(id: String) -> Dictionary:
 # ---------------------------------------------------------------- building
 
 ## hud.gd hook: builds the skill window into its body. Returns true (the old list is not built).
+static var _sig := ""
+
+
 static func fill(hud) -> bool:
 	var body: VBoxContainer = hud.bodies["skills"]
+	# rebuild only when something shown changed (a rebuild between mouse-down and -up swallowed Learn clicks)
+	var ps0 = PlayerState
+	var sig := JSON.stringify([tab, selected, ps0.skills, ps0.skill_points, str(ps0.job), ps0.ch.wheel if ps0.ch else {},
+		int(ps0.base_lv), SkillReset.check(ps0.ch) if ps0.ch else "", ps0.hotbar])
+	if sig == _sig and body.get_child_count() > 0:
+		return true
+	_sig = sig
 	hud._clear(body)
 	hud.windows["skills"].custom_minimum_size = Vector2(880, 0)
 	var ps = PlayerState
@@ -231,6 +241,8 @@ static func _node(hud, id: String, center: Vector2, path: Dictionary) -> Control
 	box.mouse_filter = Control.MOUSE_FILTER_STOP
 	box.tooltip_text = _tip(hud, id)
 	box.gui_input.connect(_node_input.bind(hud, id))
+	# UI v3f: sticky rich tooltip (ui/hover_tip.gd)
+	load("res://scripts/ui/hud_skin.gd").sticky(box, "skill:" + id)
 	var on_path := path.has(id)
 	var sel := id == selected
 	if sel or on_path: