Passive tooltip pipelines

Two independent code paths render a hover tooltip for a world object, and they gate on DIFFERENT fields of the same PassiveTooltip struct. The crosshair pipeline (normal first-person play) displays a passive tooltip only when Title is non-empty; the mouse-control pipeline (the ALT free-cursor mode) renders whenever any populated field exists, Extended alone included. A mod appending hover text must know which pipeline it is feeding. (The PassiveTooltip struct body, the Device -> Structure -> Thing dispatch chain, and the TextMeshPro render path are on ElectricalInputOutput, "GetPassiveTooltip: body-hover tooltip resolution chain".)

The law

• An Extended-only tooltip renders under mouse control (ALT) but NEVER on a crosshair hover.
• A mod appending hover text to a passive tooltip must fill Title for crosshair visibility; Extended alone is invisible there.
• Crosshair hovers that resolve to a tool action bypass GetPassiveTooltip output entirely: the displayed tooltip is built from the DelayedActionInstance, so a GetPassiveTooltip patch never affects those hovers.
• An undamaged Structure with no ExtendedTooltips gate passing produces the all-empty base tooltip, which neither pipeline renders: crosshair fails the Title gate, mouse control has every _has* flag false.

Crosshair pipeline: InventoryManager.NormalModeThing requires a non-empty Title

InventoryManager.NormalModeThing() (declared at decompile 287864 at 0.2.6403.27689) is the per-frame crosshair-hover handler in normal play. It asks the hovered thing for its passive tooltip once (287869):

PassiveTooltip cursorPassiveTooltip2 = ((CursorManager.CursorThing != null) ? CursorManager.CursorThing.GetPassiveTooltip(cursorTargetCollider) : default(PassiveTooltip));

When the hover carries a tool action (a DelayedActionInstance from AttackWith / InteractWith previews), the displayed tooltip is constructed from the action instance instead, bypassing cursorPassiveTooltip2. The two action-built sites (287917-287923 and 287947-287953), verbatim:

if (delayedActionInstance3 != null)
{
    color = ((!delayedActionInstance3.IsDisabled) ? ((delayedActionInstance3.Duration > 0f) ? UnityEngine.Color.yellow : UnityEngine.Color.green) : UnityEngine.Color.red);
    PassiveTooltip cursorPassiveTooltip3 = new PassiveTooltip(delayedActionInstance3, string.Empty, CursorManager.CursorThing);
    cursorPassiveTooltip3.color = color;
    TooltipRef.HandleToolTipDisplay(cursorPassiveTooltip3);
}

else if (delayedActionInstance != null)
{
    color = ((!delayedActionInstance.IsDisabled) ? ((delayedActionInstance.Duration > 0f) ? UnityEngine.Color.yellow : UnityEngine.Color.green) : UnityEngine.Color.red);
    PassiveTooltip cursorPassiveTooltip5 = new PassiveTooltip(delayedActionInstance, string.Empty, CursorManager.CursorThing);
    cursorPassiveTooltip5.color = color;
    TooltipRef.HandleToolTipDisplay(cursorPassiveTooltip5);
}

The GetPassiveTooltip result reaches the renderer through exactly one branch, and that branch is gated on a non-empty Title (287963-287967), verbatim:

else if (!cursorPassiveTooltip2.Title.Equals(string.Empty))
{
    TooltipRef.HandleToolTipDisplay(cursorPassiveTooltip2);
    CursorManager.ClearLastSelectionId();
}

A passive tooltip whose Title is empty never reaches HandleToolTipDisplay on this pipeline, no matter how much Extended text it carries.

Mouse-control pipeline: InputMouse.Idle hands over unconditionally

InputMouse (public class InputMouse : UserInterfaceBase, 239369) drives the ALT free-cursor mode. Its Idle() handler (239679) sources the tooltip from the same producer (239691: passiveTooltip = CursorThing.GetPassiveTooltip(hitInfo.collider);) but hands it to the renderer with NO field gate at all (239716-239721), verbatim:

if (interactable != null)
{
    Tooltip.SetValuesForInteractable(ref passiveTooltip, CursorThing, interactable);
}
passiveTooltip.FollowMouseMovement = true;
InventoryManager.Instance.TooltipRef.HandleToolTipDisplay(passiveTooltip);

The visibility decision happens inside Tooltip.HandleToolTipDisplay (public class Tooltip : UserInterfaceBase, 253966; method at 254322), where a non-empty Extended is sufficient on its own: the panel-visible flag flag2 includes _hasExtended, and the extended block toggles on its own flag. Verbatim (254322-254351, trimmed after the per-block toggles):

public void HandleToolTipDisplay(PassiveTooltip cursorPassiveTooltip)
{
    WantDraw = true;
    if ((bool)InventoryManager.ParentHuman && (bool)InventoryManager.Instance.ActiveHand.Slot.Occupant && InventoryManager.Instance.ActiveHand.Slot.Occupant is Tablet)
    {
        return;
    }
    SetUpToolTip(cursorPassiveTooltip.Action, cursorPassiveTooltip);
    bool flag = !InventoryManager.Instance.UIProgressionBar.IsVisible && (cursorPassiveTooltip.ShowRotate || cursorPassiveTooltip.ShowScroll || (cursorPassiveTooltip.ShowAction && _hasAction));
    bool flag2 = !InventoryManager.Instance.UIProgressionBar.IsVisible && (_hasAction || _hasConstruction || _hasDeconstruction || _hasPlacement || _hasState || _hasTitle || _hasRepair || _hasExtended);
    if (!flag2 && !flag)
    {
        UiComponentRenderer.SetVisible(isVisble: false);
        return;
    }
    if (!UiComponentRenderer.IsVisible)
    {
        UiComponentRenderer.SetVisible(isVisble: true);
    }
    FullToolTipHotKeys.SetVisible(flag);
    FullToolTipPanel.SetVisible(flag2);
    if (flag2)
    {
        InfoConstructionGameObject.SetVisible(_hasConstruction);
        InfoRepairGameObject?.SetVisible(_hasRepair);
        InfoDeconstructGameObject.SetVisible(_hasDeconstruction);
        InfoPlacementGameObject.SetVisible(_hasPlacement);
        StateRenderer.SetVisible(_hasState);
        ExtendedRenderer.SetVisible(_hasExtended);
        TitleRenderer.SetVisible(_hasTitle);

(_hasExtended = !string.IsNullOrEmpty(_extended) && _extended.Length > 0; is computed inside SetUpToolTip at 254314.) So under mouse control an Extended-only tooltip renders: the panel shows with only the extended block visible. The crosshair pipeline funnels through this same method, but only after its own Title gate upstream; the asymmetry lives in the callers, not here.

Producer gates: Structure.GetPassiveTooltip returns the all-empty tooltip unless an ExtendedTooltips gate passes

The base producer is Thing.GetPassiveTooltip (319731-319734), which returns a defaulted struct whose every string is empty. Verbatim, plus the head of the PassiveTooltip(bool) constructor (307089-307104; the body continues past the excerpt):

public virtual PassiveTooltip GetPassiveTooltip(Collider hitCollider)
{
    return new PassiveTooltip(true);
}

public PassiveTooltip(bool toDefault = true)
{
    Title = string.Empty;
    Action = string.Empty;
    State = string.Empty;
    Extended = string.Empty;
    RepairString = string.Empty;
    DeconstructString = string.Empty;
    ConstructString = string.Empty;
    PlacementString = string.Empty;
    ShowRotate = false;
    ShowScroll = false;
    ShowConstructionRotate = false;
    ShowAction = true;
    BuildStateIndexMessage = string.Empty;
    color = UnityEngine.Color.white;

Structure.GetPassiveTooltip (314440-314471) falls through to that empty base for every undamaged structure unless one of three gates passes. ALL three require the vanilla ExtendedTooltips game setting (Settings.CurrentData.ExtendedTooltips); the build and deconstruct gates additionally require an IShowBuildStateTooltip item in the active hand (the build gate waives the hand requirement in the upgrade-state case). Verbatim (gates 314388-314438, method 314440-314471):

private bool ShowBuildTooltip()
{
    bool flag = IsUpgradeState();
    if (Settings.CurrentData.ExtendedTooltips && (flag || !IsStructureCompleted) && NextBuildState != null)
    {
        if (!flag)
        {
            Slot activeHandSlot = InventoryManager.ActiveHandSlot;
            if (activeHandSlot != null)
            {
                return activeHandSlot.Occupant is IShowBuildStateTooltip;
            }
            return false;
        }
        return true;
    }
    return false;
}

private bool ShowDeconstructTooltip()
{
    if (Settings.CurrentData.ExtendedTooltips && (bool)InventoryManager.Parent)
    {
        Slot activeHandSlot = InventoryManager.ActiveHandSlot;
        if (activeHandSlot != null)
        {
            return activeHandSlot.Occupant is IShowBuildStateTooltip;
        }
        return false;
    }
    return false;
}

private bool ShowRepairTooltip()
{
    if (Settings.CurrentData.ExtendedTooltips && RepairTools.IsValid())
    {
        return DamageState.Total > 0f;
    }
    return false;
}

private bool IsUpgradeState()
{
    ToolUseType? toolUseType = NextBuildState?.Tool?.ToolUseType;
    if (toolUseType.HasValue)
    {
        return toolUseType == ToolUseType.Upgrade;
    }
    return false;
}

public override PassiveTooltip GetPassiveTooltip(Collider hitCollider)
{
    bool flag = ShowBuildTooltip();
    bool flag2 = ShowDeconstructTooltip();
    bool flag3 = ShowRepairTooltip();
    if (DamageState.Total <= 0f && !flag && !flag2 && !flag3)
    {
        return base.GetPassiveTooltip(hitCollider);
    }
    PassiveTooltip passiveTooltip = new PassiveTooltip(true);
    passiveTooltip.Title = DisplayName;
    passiveTooltip.Extended = GetExtendedText().ToString();
    PassiveTooltip result = passiveTooltip;
    if (flag)
    {
        result.ConstructString = NextBuildState.Tool.GetToolsAsString();
    }
    if (IsBroken && BrokenBuildStates.Count > 0)
    {
        int index = Mathf.Clamp(Mathf.Abs(CurrentBuildStateIndex) - 1, 0, BrokenBuildStates.Count - 1);
        result.DeconstructString = BrokenBuildStates[index].BuildState.Tool.GetExitToolAsString();
    }
    else
    {
        result.DeconstructString = CurrentBuildState.Tool.GetExitToolAsString();
    }
    if (flag3)
    {
        result.RepairString = RepairTools.GetRepairsAsString();
    }
    return result;
}

Gate census:

Gate	Requires
ShowBuildTooltip (314388-314405)	ExtendedTooltips AND (IsUpgradeState() OR not IsStructureCompleted) AND NextBuildState != null; when not upgrade-state, ALSO active-hand occupant is IShowBuildStateTooltip
ShowDeconstructTooltip (314407-314419)	ExtendedTooltips AND InventoryManager.Parent AND active-hand occupant is IShowBuildStateTooltip
ShowRepairTooltip (314421-314428)	ExtendedTooltips AND RepairTools.IsValid() AND DamageState.Total > 0f

When DamageState.Total <= 0f and no gate passes, the return is the all-empty base tooltip: invisible on both pipelines. When any gate passes (or the structure is damaged), the struct gets Title = DisplayName and Extended = GetExtendedText().ToString() plus the construct / deconstruct / repair strings.

Mod consequences

• A Structure.GetPassiveTooltip postfix that only appends to __result.Extended is invisible to crosshair players whenever the vanilla body fell through to the empty base (undamaged structure, gates closed): Title stayed empty and NormalModeThing's gate at 287963 drops the tooltip. Set __result.Title (typically __instance.DisplayName) in the same postfix.
• Concrete case: CableRuptured wreckage spawns undamaged (DamageState.Total == 0, see Cable, "The wreckage spawns undamaged"), so a burn-reason annotation on the wreckage must fill Title to show on a crosshair hover; Extended-only text appears solely in the ALT mouse-control hover.
• Tool-action hovers (crosshair with a tool in hand producing a DelayedActionInstance) never consult GetPassiveTooltip output; annotating those requires touching the action-instance path (287920 / 287950), not the passive-tooltip producer.

Per-class Title filling: which device bodies render Extended-only text on a crosshair hover

The crosshair Title gate makes the practical visibility of an appended Extended line depend on whether the hovered class's own GetPassiveTooltip override fills Title. Census at 0.2.6403.27689:

Title-FILLING bodies (Extended-only annotations DO render on a bare crosshair hover):

• SolarPanel.GetPassiveTooltip (421384-421397): when fully built, always sets Title = DisplayName plus State = SolarInfo().
• PowerGeneratorPipe.GetPassiveTooltip (396655-396675): fills Title = DisplayName whenever the base chain left it empty.
• StirlingEngine.GetPassiveTooltip (424241-424269): same pattern.
• AreaPowerControl.GetPassiveTooltip (390800-390810): the null-collider body poll gets Title = DisplayName plus the charge readout in Extended.
• Any DAMAGED structure (the damage gate fills a repair tooltip) and any Input / Output port collider on the ElectricalInputOutput family (395008-395023 titles the port colliders).

Title-LESS bodies (Extended-only annotations render ONLY under ALT):

• The ElectricalInputOutput family body hover (Transformer, Battery, PowerTransmitter, PowerReceiver, both umbilical halves): only port colliders are titled.
• PowerConnector (408050-408059): only its input-port collider.
• Every class that falls through to the empty base tooltip (Thing 319731-319734), including undamaged wreckage.

The cursor-target accessor

The Thing under the crosshair or mouse resolves through CursorManager.CursorThing (class CursorManager : ManagerBase in namespace Assets.Scripts, decompile 200808; example vanilla consumer at 115374). A mod patch bracketing InventoryManager.NormalModeThing with a flag and completing the tooltip at Tooltip.HandleToolTipDisplay (Assets.Scripts.UI.Tooltip) can therefore attribute the displayed tooltip to the cursor target and append or Title-fill additively, covering the tool-in-hand branches that bypass GetPassiveTooltip; PowerGridPlus's CursorTooltipChokePatches is the working example.

Verification history

• 2026-07-18: added the cursor-target accessor section (CursorManager.CursorThing, Assets.Scripts namespace, decompile 200808) with the choke-point pattern note.
• 2026-07-18: added the per-class Title-filling census (SolarPanel / PowerGeneratorPipe / StirlingEngine / AreaPowerControl fill Title on the body; the ElectricalInputOutput family and PowerConnector title only port colliders), read from the 0.2.6403.27689 decompile during the hover-surface matrix review.
• 2026-07-18: page created (game version 0.2.6403.27689). All quoted lines read directly from .work/decomp/0.2.6403.27689/Assembly-CSharp.decompiled.cs; the findings were produced and independently adversarially verified against the decompile this session. Crosshair pipeline: InventoryManager.NormalModeThing (287864) builds the hover tooltip from GetPassiveTooltip (287869) and displays it only when Title is non-empty (287963); tool-action hovers build PassiveTooltip(DelayedActionInstance, ...) directly (287920, 287950). Mouse-control pipeline: InputMouse.Idle (239679, tooltip sourced at 239691) hands the tooltip to HandleToolTipDisplay unconditionally (239720-239721); Tooltip.HandleToolTipDisplay (254322) treats a non-empty Extended as sufficient (flag2 includes _hasExtended at 254331; ExtendedRenderer.SetVisible(_hasExtended) at 254350). Producer gates: Structure.GetPassiveTooltip (314440-314471) with the three ExtendedTooltips-gated helpers (314388-314428) and the all-empty Thing base (319731-319734; PassiveTooltip(bool) zeroes Title at 307091).

Open questions

None.