docs: update to next version [BUMP BETA] (#4493)

platform/docs/versioned_docs/version-3.9/migration-guide/3p8-to-3p9/9-other.md

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+---
+title: Other Changes
+---
+
+import Tabs from '@theme/Tabs';
+import TabItem from '@theme/TabItem';
+
+
+## External Libraries
+Some libraries are loaded via dynamic import.  You can provide a global function
+`browserImport` the allows loading of dynamic imports without affecting the
+webpack build.  This import looks like:
+
+```html
+<script>
+  function browserImportFunction(moduleId) {
+    return import(moduleId);
+  }
+</script>
+```
+
+and belongs in the root html file for your application.
+You then need to remove `dependencies` on the external import, and add a reference
+to the external import in your `pluginConfig.json` file.
+
+### Example plugin config for `dicom-microscopy-viewer`
+The example below imports the `dicom-microscopy-viewer` for use as an external
+dependency.  The example is part of the default `pluginConfig.json` file.
+
+```json
+  "public": [
+    {
+      "directory": "./platform/public"
+    },
+    {
+      "packageName": "dicom-microscopy-viewer",
+      "importPath": "/dicom-microscopy-viewer/dicomMicroscopyViewer.min.js",
+      "globalName": "dicomMicroscopyViewer",
+      "directory": "./node_modules/dicom-microscopy-viewer/dist/dynamic-import"
+    }
+  ]
+```
+
+This defines two directory modules, whose contents are copied unchanged to the
+output build directory.  It then defines the `dicom-microscopy-viewer` using
+the `packageName` element as being a module which is imported dynamically.
+Then, the import path passed into the browserImportFunction above is
+specified, and then how to access the import itself, via the `window.dicomMicroscopyViewer`
+global name reference.
+
+### Referencing External Imports
+The appConfig either defines or has a default peerImport function which can be
+used to load references to the modules defined in the pluginConfig file.  See
+the example in `init.tsx` for the cornerstone extension for how this is passed
+into CS3D for loading the whole slide imaging library.
+
+
+
+---
+
+
+
+---
+
+
+---
+
+
+## Use of ViewReference for navigation
+When navigating to measurements and storing/remembering navigation positions,
+the `viewport.getViewReference` is used to get a position, and `viewport.isReferenceViewable`
+used to check if a reference can be applied, and finally `viewport.setViewReference` to
+navigate to a view.  Note that this changes the behaviour of navigation between
+MPR and Stack viewports, and also enables navigation of video and microscopy
+viewports in CS3D.  This can cause some unexpected behaviour depending on how the
+frame of reference values are configured to allow for navigation.
+
+The isReferenceViewable is used to determine when a view or measurement can be
+shown on a given view.  For stack versus volume viewports, this can cause unexpected
+behaviour to be seen depending on how the view reference was fetched.
+
+### `getViewReference` with `forFrameOfReference`
+When a view reference is fetched with the for frame of reference flag set to true,
+a reference will be returned which can be displayed on any viewport containing
+the same frame of reference and encompassing the given FOR and able to display the required
+orientation.  Without this flag, a view reference is returned which will be
+displayed on a stack with the given image id, or a volume containing said image id
+or the specified volume.
+
+### `isReferenceViewable` with navigation and/or orientation
+The is reference viewable will return false unless the given reference is directly
+viewable in the viewport as is.  However, it can be passed various flags to determine
+whether the reference could be displayed if the viewport was modified in various ways,
+for example, by changing the position or orientation of the viewport.  This allows
+checking for degrees of closeness so that the correct viewport can be chosen.
+
+Note that this may result in displaying a measurement from one viewport on a completely
+different viewport, for example, showing a Probe tool from the stack viewport on
+an MPR view.