SlimeStorm

protonopen appid 4564980Game compatibility - Unofficial.NET

ValveSoftware/Proton#10024 · opened 2026-07-31 by williewillus · updated 2026-08-01 · 3 comments · github · game page · search this game

Wwilliewillus 2026-07-31 github

Compatibility Report

Name of the game with compatibility issues: SlimeStorm
Steam AppID of the game: 4564980

System Information

GPU: AMD Radeon 780M
Video driver version: 26.1.3-2
Kernel version: 7.0.13
Link to full system information report as Gist:
Proton version: Default

I confirm:

[x] that I haven't found an existing compatibility report for this game.
[x] that I have checked whether there are updates for my system available.

Symptoms

Main UI opens, but most operations throw .NET exceptions

Reproduction

Launch the program
Add an emitter with the button in the toolbar
Try dragging it around, see error popup
Click around the UI, most other buttons also error

VVoidCounsel 2026-08-01 github

@williewillus one quick detail that would help a lot: Steam’s “Default” doesn’t record which Proton build actually ran. in the app’s Properties > Compatibility, what does it show as the selected tool (e.g. Proton 11.0-1, Experimental, or something else)? that version pin is what makes the .NET exceptions actionable

Wwilliewillus 2026-08-01 github

@williewillus one quick detail that would help a lot: Steam’s “Default” doesn’t record which Proton build actually ran. in the app’s Properties > Compatibility, what does it show as the selected tool (e.g. Proton 11.0-1, Experimental, or something else)? that version pin is what makes the .NET exceptions actionable

I don't have "Force use of a specific Steam Play compatibility tool" checked, so there's no version to choose. I tested again with Proton 11, 10, and Experimental, and the same error happens in each.

For convenience, here's the exception that appears when trying to drag an emitter:

See the end of this message for details on invoking 
just-in-time (JIT) debugging instead of this dialog box.

************** Exception Text **************
System.InvalidCastException: Specified cast is not valid.
  at System.Windows.Forms.PropertyGridInternal.PropertyDescriptorGridEntry.get_UITypeEditor () [0x0002e] in <44e771661495434ea7220c120f0bccc0>:0 
  at System.Windows.Forms.PropertyGridInternal.GridEntry.get_Flags () [0x0003d] in <44e771661495434ea7220c120f0bccc0>:0 
  at System.Windows.Forms.PropertyGridInternal.GridEntry.GetFlagSet (System.Int32 flag) [0x00001] in <44e771661495434ea7220c120f0bccc0>:0 
  at System.Windows.Forms.PropertyGridInternal.GridEntry.get_Expandable () [0x00001] in <44e771661495434ea7220c120f0bccc0>:0 
  at System.Windows.Forms.PropertyGridInternal.PropertyGridView.SetExpand (System.Windows.Forms.PropertyGridInternal.GridEntry gridEntry, System.Boolean value) [0x00004] in <44e771661495434ea7220c120f0bccc0>:0 
  at System.Windows.Forms.PropertyGridInternal.PropertyGridView.RecursivelyExpand (System.Windows.Forms.PropertyGridInternal.GridEntry gridEntry, System.Boolean fInit, System.Boolean expand, System.Int32 maxExpands) [0x0001e] in <44e771661495434ea7220c120f0bccc0>:0 
  at System.Windows.Forms.PropertyGridInternal.PropertyGridView.RecursivelyExpand (System.Windows.Forms.PropertyGridInternal.GridEntry gridEntry, System.Boolean fInit, System.Boolean expand, System.Int32 maxExpands) [0x00042] in <44e771661495434ea7220c120f0bccc0>:0 
  at System.Windows.Forms.PropertyGridInternal.PropertyGridView.RecursivelyExpand (System.Windows.Forms.PropertyGridInternal.GridEntry gridEntry, System.Boolean fInit, System.Boolean expand, System.Int32 maxExpands) [0x00042] in <44e771661495434ea7220c120f0bccc0>:0 
  at (wrapper remoting-invoke-with-check) System.Windows.Forms.PropertyGridInternal.PropertyGridView.RecursivelyExpand(System.Windows.Forms.PropertyGridInternal.GridEntry,bool,bool,int)
  at System.Windows.Forms.PropertyGrid.ExpandAllGridItems () [0x00001] in <44e771661495434ea7220c120f0bccc0>:0 
  at (wrapper remoting-invoke-with-check) System.Windows.Forms.PropertyGrid.ExpandAllGridItems()
  at SlimeStorm.FormMainV2.UpdatePropertySelectItems () [0x000b1] in <14f2863fef3341608513a1b93bd8e0e9>:0 
  at SlimeStorm.FormMainV2.Uo_MouseDown (System.Object sender, System.Windows.Forms.MouseEventArgs e) [0x00259] in <14f2863fef3341608513a1b93bd8e0e9>:0 
  at System.Windows.Forms.Control.OnMouseDown (System.Windows.Forms.MouseEventArgs e) [0x0001f] in <44e771661495434ea7220c120f0bccc0>:0 
  at System.Windows.Forms.UserControl.OnMouseDown (System.Windows.Forms.MouseEventArgs e) [0x00015] in <44e771661495434ea7220c120f0bccc0>:0 
  at System.Windows.Forms.Control.WmMouseDown (System.Windows.Forms.Message& m, System.Windows.Forms.MouseButtons button, System.Int32 clicks) [0x000d6] in <44e771661495434ea7220c120f0bccc0>:0 
  at System.Windows.Forms.Control.WndProc (System.Windows.Forms.Message& m) [0x0058d] in <44e771661495434ea7220c120f0bccc0>:0 
  at System.Windows.Forms.ScrollableControl.WndProc (System.Windows.Forms.Message& m) [0x00043] in <44e771661495434ea7220c120f0bccc0>:0 
  at System.Windows.Forms.ContainerControl.WndProc (System.Windows.Forms.Message& m) [0x0001a] in <44e771661495434ea7220c120f0bccc0>:0 
  at System.Windows.Forms.UserControl.WndProc (System.Windows.Forms.Message& m) [0x0001a] in <44e771661495434ea7220c120f0bccc0>:0 
  at System.Windows.Forms.Control+ControlNativeWindow.OnMessage (System.Windows.Forms.Message& m) [0x00001] in <44e771661495434ea7220c120f0bccc0>:0 
  at System.Windows.Forms.Control+ControlNativeWindow.WndProc (System.Windows.Forms.Message& m) [0x000b3] in <44e771661495434ea7220c120f0bccc0>:0 
  at System.Windows.Forms.NativeWindow.Callback (System.Windows.Forms.Message& m) [0x00025] in <44e771661495434ea7220c120f0bccc0>:0 


************** Loaded Assemblies **************
mscorlib
    Assembly Version: 4.0.0.0
    Win32 Version: 4.6.57.0
    CodeBase: file:///S:/common/Proton%20-%20Experimental/files/share/wine/mono/wine-mono/lib/mono/4.5/mscorlib.dll
----------------------------------------
SlimeStorm
    Assembly Version: 1.0.0.0
    Win32 Version: 1.0.0.0
    CodeBase: file:///S:/common/SlimeStorm/SlimeStorm.exe
----------------------------------------
System.Windows.Forms
    Assembly Version: 4.0.0.0
    Win32 Version: 4.6.57.0
    CodeBase: file:///S:/common/Proton%20-%20Experimental/files/share/wine/mono/wine-mono/lib/mono/gac/System.Windows.Forms/4.0.0.0__b77a5c561934e089/System.Windows.Forms.dll
----------------------------------------
System
    Assembly Version: 4.0.0.0
    Win32 Version: 4.6.57.0
    CodeBase: file:///S:/common/Proton%20-%20Experimental/files/share/wine/mono/wine-mono/lib/mono/gac/System/4.0.0.0__b77a5c561934e089/System.dll
----------------------------------------
SlimeForm
    Assembly Version: 1.0.0.0
    Win32 Version: 1.0.0.0
    CodeBase: file:///S:/common/SlimeStorm/SlimeForm.dll
----------------------------------------
System.Drawing
    Assembly Version: 4.0.0.0
    Win32 Version: 4.6.57.0
    CodeBase: file:///S:/common/Proton%20-%20Experimental/files/share/wine/mono/wine-mono/lib/mono/gac/System.Drawing/4.0.0.0__b03f5f7f11d50a3a/System.Drawing.dll
----------------------------------------
Accessibility
    Assembly Version: 4.0.0.0
    Win32 Version: 
    CodeBase: file:///S:/common/Proton%20-%20Experimental/files/share/wine/mono/wine-mono/lib/mono/gac/Accessibility/4.0.0.0__b03f5f7f11d50a3a/Accessibility.dll
----------------------------------------
BulletPlayer
    Assembly Version: 1.0.0.0
    Win32 Version: 1.0.0.0
    CodeBase: file:///S:/common/SlimeStorm/BulletPlayer.dll
----------------------------------------
Barrage
    Assembly Version: 1.0.0.0
    Win32 Version: 1.0.0.0
    CodeBase: file:///S:/common/SlimeStorm/Barrage.dll
----------------------------------------
GlassButton
    Assembly Version: 1.3.0.2614
    Win32 Version: 1.3.0.2614
    CodeBase: file:///S:/common/SlimeStorm/GlassButton.dll
----------------------------------------
ReaLTaiizor
    Assembly Version: 3.8.1.5
    Win32 Version: 3.8.1.5
    CodeBase: file:///S:/common/SlimeStorm/ReaLTaiizor.dll
----------------------------------------
System.Configuration
    Assembly Version: 4.0.0.0
    Win32 Version: 4.6.57.0
    CodeBase: file:///S:/common/Proton%20-%20Experimental/files/share/wine/mono/wine-mono/lib/mono/gac/System.Configuration/4.0.0.0__b03f5f7f11d50a3a/System.Configuration.dll
----------------------------------------
Facepunch.Steamworks.Win32
    Assembly Version: 1.0.0.0
    Win32 Version: 2.5.0
    CodeBase: file:///S:/common/SlimeStorm/Facepunch.Steamworks.Win32.dll
----------------------------------------
System.Core
    Assembly Version: 4.0.0.0
    Win32 Version: 4.6.57.0
    CodeBase: file:///S:/common/Proton%20-%20Experimental/files/share/wine/mono/wine-mono/lib/mono/gac/System.Core/4.0.0.0__b77a5c561934e089/System.Core.dll
----------------------------------------
SlimeStorm.resources
    Assembly Version: 1.0.0.0
    Win32 Version: 1.0.0.0
    CodeBase: file:///S:/common/SlimeStorm/en/SlimeStorm.resources.dll
----------------------------------------
WineMono.I18N
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.0.0
    CodeBase: file:///S:/common/Proton%20-%20Experimental/files/share/wine/mono/wine-mono/lib/mono/gac/WineMono.I18N/4.0.0.0__0738eb9f132ed756/WineMono.I18N.dll
----------------------------------------
WineMono.I18N.West
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.0.0
    CodeBase: file:///S:/common/Proton%20-%20Experimental/files/share/wine/mono/wine-mono/lib/mono/gac/WineMono.I18N.West/4.0.0.0__0738eb9f132ed756/WineMono.I18N.West.dll
----------------------------------------
System.Xml
    Assembly Version: 4.0.0.0
    Win32 Version: 4.6.57.0
    CodeBase: file:///S:/common/Proton%20-%20Experimental/files/share/wine/mono/wine-mono/lib/mono/gac/System.Xml/4.0.0.0__b77a5c561934e089/System.Xml.dll
----------------------------------------
Microsoft.GeneratedCode
    Assembly Version: 1.0.0.0
    Win32 Version: n/a
    CodeBase: 
----------------------------------------
Newtonsoft.Json
    Assembly Version: 13.0.0.0
    Win32 Version: 13.0.5.31230
    CodeBase: file:///S:/common/SlimeStorm/Newtonsoft.Json.dll
----------------------------------------
Microsoft.GeneratedCode
    Assembly Version: 1.0.0.0
    Win32 Version: n/a
    CodeBase: 
----------------------------------------
WineMono.Security
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.0.0
    CodeBase: file:///S:/common/Proton%20-%20Experimental/files/share/wine/mono/wine-mono/lib/mono/gac/WineMono.Security/4.0.0.0__0738eb9f132ed756/WineMono.Security.dll
----------------------------------------
Barrage.resources
    Assembly Version: 1.0.0.0
    Win32 Version: 1.0.0.0
    CodeBase: file:///S:/common/SlimeStorm/en/Barrage.resources.dll
----------------------------------------
System.Design
    Assembly Version: 4.0.0.0
    Win32 Version: 4.6.57.0
    CodeBase: file:///S:/common/Proton%20-%20Experimental/files/share/wine/mono/wine-mono/lib/mono/gac/System.Design/4.0.0.0__b03f5f7f11d50a3a/System.Design.dll
----------------------------------------

************** JIT Debugging **************

VVoidCounsel 2026-08-01 github

This clarifies the picture significantly

System.InvalidCastException in PropertyDescriptorGridEntry.get_UITypeEditor, during PropertyGrid.ExpandAllGridItems, fired from FormMainV2.UpdatePropertySelectItems on mouse down. so selecting/dragging an emitter refreshes the WinForms property panel, and Wine-Mono’s PropertyGrid hits an invalid cast while resolving a UITypeEditor

the loaded assemblies confirm it’s Wine-Mono (.../wine-mono/lib/mono/...), not native .NET Framework 4.8. same failure on 10, 11, and Experimental fits that: those builds still hand Framework apps to Mono unless the prefix has real dotnet48

so this looks like Wine-Mono WinForms PropertyGrid, invalid cast on UITypeEditor during expand, on emitter selection, rather than a vague “.NET is broken under Proton” problem

@williewillus next check is to get real .NET Framework 4.8 into this prefix instead of Wine-Mono

protontricks 4564980 dotnet48

that installs Microsoft’s Framework into the SlimeStorm bottle. launch the app again and drag an emitter the same way

if the exception stops, the bad cast was in Mono’s PropertyGrid and native Framework avoids it
if it still throws, the same PropertyGrid path is failing even on real Framework, which points at Wine’s WinForms support underneath rather than Mono’s class library

Proton versions

proton 11.0-1x2 2026-08

DLLs

accessibility.dllx1 2026-08
barrage.dllx1 2026-08
bulletplayer.dllx1 2026-08
configuration.dllx1 2026-08
core.dllx1 2026-08
design.dllx1 2026-08
drawing.dllx1 2026-08
forms.dllx1 2026-08
glassbutton.dllx1 2026-08
i18n.dllx1 2026-08
json.dllx1 2026-08
mscorlib.dllx1 2026-08
realtaiizor.dllx1 2026-08
resources.dllx1 2026-08
security.dllx1 2026-08