name: gum-shared-source
description: FRB vs MonoGameGum source-sharing model — same .cs files, separate .csproj, and where the two diverge. Triggers: Compile Include Gum, GumRuntime, MonoGameGum, Cursor, shared source file missing on FRB side.
Gum Shared Source (FRB vs MonoGameGum)
MonoGameGum (in the sibling [[gum-integration]] repo) is the primary, more widely-used consumer of Gum's runtime. FRB reuses the bulk of that same source (roughly 80-90%) rather than forking it, but the two have separate .csproj files — there is no shared project file. FRB's projects pull individual Gum source files in directly via <Compile Include> with a relative path into the sibling repo (e.g. GumPlugin.csproj includes ..\..\..\..\..\Gum\GumRuntime\BbCodeParser.cs), alongside plain <ProjectReference>s to fully-shared sub-libraries like GumCommon/GumCore.
Gotcha: a new/renamed file in Gum's source does not automatically appear on the FRB side. Since FRB's .csproj lists individual files rather than referencing the folder, adding a file in MonoGameGum/GumRuntime requires also adding a matching <Compile Include> line in the FRB-side .csproj (GumPlugin.csproj, FlatRedBall.Forms.*.csproj, etc.) or it silently won't compile in.
Gotcha: not everything is shared — some types are FRB's own, same-named or not. The flagship example is Cursor: MonoGameGum has its own MonoGameGum.Input.Cursor, but FRB doesn't use it — FRB has its own, older FlatRedBall.Gui.Cursor (Engines\FlatRedBallXNA\FlatRedBall\Gui\Cursor.cs), bridged to Gum via extension methods (CursorExtensions.cs, e.g. XRespectingGumZoomAndBounds) instead of sharing the type. Before assuming a Gum API applies on the FRB side, check which repo/namespace it actually lives in.
