file size limit and fixed positioning warning added and migration guided moved

Author: Steve Kwak

SUMMARY.md

@@ -162,5 +162,5 @@
   * [How to contribute](./CONTRIBUTING.md)
 * [Migrations](./migrations.md)
   * [UXP 2 to 3](./migrations/uxp-2-to-3.md)
-  * [Porting Modals to Panels](./tutorials/how-to-migrate-from-modal-to-panel/index.md)
+  * [Porting Modals to Panels](./migrations/how-to-migrate-from-modal-to-panel.md)
 * [Plugin API roadmap](./plugin-api-roadmap.md)

distribution/packaging.md

@@ -20,7 +20,7 @@ Select all files within your plugin's parent folder. On both macOS and Windows y
 | macOS         | _Right-click > Compress # items_ |
 | Windows       | _Right-click > Send to > Compressed (zipped) folder_ |
 
-If you plan to distribute via the XD plugin manager, your .ZIP file **must be less than 25MB in size**. You'll only be able to submit for review if your file is under the size limit.
+If you plan to distribute via the XD plugin manager, your .ZIP file **must be less than 25MB in size and contain fewer than 3,000 files**. You'll only be able to submit for review if your file is under these limits.
 
 > **Danger**
 >

migrations/uxp-2-to-3.md

@@ -1,3 +1,6 @@
+> **warning**
+> Please refrain from using `position: fixed` if you are building a [panel](/reference/ui/panels/index.md) plugin. Currently, there is a bug that allows panels to put elements outside the panel boundaries. This will break your panel plugin in a future release when the bug is fixed.
+
 # Relative and Absolute Positioning
 
 You can use relative and absolute positioning to indicate _exactly_ where elements are to be positioned. Relative positioning allows you to shift an element from its originally calculated position whereas absolute positioning takes the element out of the layout flow entirely, and allows you to position the element anywhere.