docs(windows): describe windows compliant app implementation with sequence diagram

knowledge-base/assets/kb0118/windows-compliant-app-sequence.mmd

@@ -0,0 +1,26 @@
+sequenceDiagram
+    autonumber
+    participant User as User
+    participant OS as Windows OS
+    participant TSF as TSF Manager
+    participant Keyman as Keyman TIP
+    participant App as Application (Compliant)
+
+    User->>OS: Press key (e.g. 'D')
+    OS->>TSF: Deliver key event
+    TSF->>Keyman: Call OnKeyDown(ITfContext)
+
+    Note right of Keyman: Keyman create TIPEditSession & requests context
+    Keyman->>TSF: ITfContext.GetStatus()
+    Keyman->>TSF: ITfContext.GetSelection()
+    TSF->>App: Request current selection
+    App-->>TSF: Return selection
+    TSF-->>Keyman: Return GetSelection
+
+
+    Note right of Keyman: Keyman applies keyboard rules and inserts or modifies the text in the selection
+
+    Keyman->>TSF: ITfContext.SetSelection()
+    TSF->>App: Modified selection is applied to the application
+
+    App-->>User: Display “∆” in document

knowledge-base/kb0118.md

@@ -223,4 +223,32 @@ on the Keyman system service which emits a fake key event. That way it is possib
 
 ## Compliance on Windows
 
-TODO
+On Windows, Keyman integrates with applications primarily through the Text Services Framework (TSF). Keyman implements a Text Input Processor (TIP) that communicates with the TSF manager and the target application.
+
+When the user types, the TSF manager passes key events and text context to Keyman through the `ITfContext` interface, which provides access to the current edit context within the application. Keyman relies on this interface to retrieve context, as a selection object, and insert or replace text.
+For `ITfContext` details see [Learn Microsoft](https://learn.microsoft.com/en-us/windows/win32/api/msctf/nn-msctf-itfcontext).
+
+Relevant for Keyman are the following API functions:
+
+**`GetStatus()`** — Retrieves the current status of the text context. Keyman uses this to check for the `TF_SS_TRANSITORY` flag, which indicates temporary or non-standard contexts that may not behave consistently.
+
+**`GetSelection()`** — Used by Keyman for Windows to get the context next to the cursor.
+
+**`SetSelection()`** — Updates the current selection or caret position after Keyman inserts or replaces text in the selection retrieved with `GetSelection()`.
+
+
+Keyman determines whether an application is compliant by inspecting the status returned by `ITfContext::GetStatus()`. Compliant applications provide a stable, non-transitory context and correctly implement the TSF APIs needed to retrieve context and modify text.
+
+Applications can restrict how much surrounding text can be read; Keyman limits its requests to 64 characters of context.
+
+<img src="./assets/kb0118/windows-compliant-app-sequence.png" width="75%" alt="compliant sequence on Windows"/>
+
+The sequence diagram is for a rule that replaces "D" with "∆". 
+
+Note: For both compliant and non-compliant apps. When there is a highlighted section of text if backspace is the determined action from processing the keystroke on Windows Keyman will emit the key (backspace), allowing the application to handle clearing selected text in the correct manner. 
+
+### Non-compliance on Windows
+
+If the `TF_SS_TRANSITORY` flag is present or context cannot be read as expected, Keyman treats the application as **non-compliant** and falls back to legacy behavior, maintaining its own internal context buffer and simulating text operations where possible.
+
+The limitations are as stated at the start of this knowledge base article [Working around non-compliant behavior](##-working-around-non-compliant-behavior). Further reading on sending a backspace to an application to perform a delete can be found on the Keyman wiki [here](https://github.com/keymanapp/keyman/wiki/Backspace-and-cluster-deletion).