diff --git a/src/library/ipc.h b/src/library/ipc.h
index bed03e9..4d11b6b 100644
--- a/src/library/ipc.h
+++ b/src/library/ipc.h
@@ -45,6 +45,7 @@ enum BoltIPCMessageTypeToClient {
     IPC_MSG_EXTERNALBROWSERMESSAGE,
     IPC_MSG_OSRBROWSERMESSAGE,
     IPC_MSG_OSRSTARTREPOSITION,
+    IPC_MSG_OSRCANCELREPOSITION,
     IPC_MSG_BROWSERCLOSEREQUEST,
     IPC_MSG_OSRCLOSEREQUEST,
 };
@@ -157,6 +158,11 @@ struct BoltIPCOsrStartRepositionHeader {
     int8_t vertical; // -1 for top edge, 1 for bottom edge
 };
 
+/// Header for BoltMessageTypeToClient::IPC_MSG_OSRCANCELREPOSITION
+struct BoltIPCOsrCancelRepositionHeader {
+    uint64_t window_id;
+};
+
 /// Header for BoltMessageTypeToClient::IPC_MSG_BROWSERCLOSEREQUEST
 struct BoltIPCBrowserCloseRequestHeader {
     uint64_t window_id;
diff --git a/src/library/plugin/plugin.c b/src/library/plugin/plugin.c
index 460fb56..e1e1964 100644
--- a/src/library/plugin/plugin.c
+++ b/src/library/plugin/plugin.c
@@ -876,10 +876,15 @@ static void handle_ipc_OSRBROWSERMESSAGE(struct BoltIPCBrowserMessageHeader* hea
 
 static void handle_ipc_OSRSTARTREPOSITION(struct BoltIPCOsrStartRepositionHeader* header, struct EmbeddedWindow* window) {
     window->reposition_mode = true;
+    window->reposition_threshold = false;
     window->reposition_w = header->horizontal;
     window->reposition_h = header->vertical;
 }
 
+static void handle_ipc_OSRCANCELREPOSITION(struct BoltIPCOsrCancelRepositionHeader* header, struct EmbeddedWindow* window) {
+    window->reposition_mode = false;
+}
+
 static void handle_ipc_BROWSERCLOSEREQUEST(struct BoltIPCBrowserCloseRequestHeader* header, struct ExternalBrowser* browser) {
     handle_close_request(browser->plugin->state, header->window_id);
 }
@@ -902,6 +907,7 @@ void _bolt_plugin_handle_messages() {
             IPCCASEBROWSERTAIL(EXTERNALBROWSERMESSAGE, BrowserMessage)
             IPCCASEWINDOWTAIL(OSRBROWSERMESSAGE, BrowserMessage)
             IPCCASEWINDOW(OSRSTARTREPOSITION, OsrStartReposition)
+            IPCCASEWINDOW(OSRCANCELREPOSITION, OsrCancelReposition)
             IPCCASEBROWSER(BROWSERCLOSEREQUEST, BrowserCloseRequest)
             IPCCASEWINDOW(OSRCLOSEREQUEST, OsrCloseRequest)
             default:
@@ -1072,13 +1078,14 @@ uint8_t _bolt_plugin_add(const char* path, struct Plugin* plugin) {
     PUSHSTRING(plugin->state, WINDOW_META_REGISTRYNAME);
     lua_newtable(plugin->state);
     PUSHSTRING(plugin->state, "__index");
-    lua_createtable(plugin->state, 0, 11);
+    lua_createtable(plugin->state, 0, 12);
     API_ADD_SUB(plugin->state, close, window)
     API_ADD_SUB(plugin->state, id, window)
     API_ADD_SUB(plugin->state, size, window)
     API_ADD_SUB(plugin->state, clear, window)
     API_ADD_SUB(plugin->state, subimage, window)
     API_ADD_SUB(plugin->state, startreposition, window)
+    API_ADD_SUB(plugin->state, cancelreposition, window)
     API_ADD_SUB(plugin->state, onreposition, window)
     API_ADD_SUB(plugin->state, onmousemotion, window)
     API_ADD_SUB(plugin->state, onmousebutton, window)
@@ -1091,9 +1098,11 @@ uint8_t _bolt_plugin_add(const char* path, struct Plugin* plugin) {
     PUSHSTRING(plugin->state, BROWSER_META_REGISTRYNAME);
     lua_newtable(plugin->state);
     PUSHSTRING(plugin->state, "__index");
-    lua_createtable(plugin->state, 0, 3);
+    lua_createtable(plugin->state, 0, 6);
     API_ADD_SUB(plugin->state, close, browser)
     API_ADD_SUB(plugin->state, sendmessage, browser)
+    API_ADD_SUB(plugin->state, startreposition, window)
+    API_ADD_SUB(plugin->state, cancelreposition, window)
     API_ADD_SUB(plugin->state, oncloserequest, browser)
     API_ADD_SUB(plugin->state, onmessage, browser)
     lua_settable(plugin->state, -3);
@@ -1954,6 +1963,13 @@ static int api_window_startreposition(lua_State* state) {
     return 0;
 }
 
+static int api_window_cancelreposition(lua_State* state) {
+    _bolt_check_argc(state, 3, "window_cancelreposition");
+    struct EmbeddedWindow* window = lua_touserdata(state, 1);
+    window->reposition_mode = false;
+    return 0;
+}
+
 static int api_render3d_vertexcount(lua_State* state) {
     _bolt_check_argc(state, 1, "render3d_vertexcount");
     const struct Render3D* render = lua_touserdata(state, 1);
diff --git a/src/library/plugin/plugin_api.h b/src/library/plugin/plugin_api.h
index 67e572f..43f0745 100644
--- a/src/library/plugin/plugin_api.h
+++ b/src/library/plugin/plugin_api.h
@@ -478,6 +478,11 @@ static int api_window_subimage(lua_State*);
 /// bottom edge. Finally, if both are zero, the window will be moved instead of resized.
 static int api_window_startreposition(lua_State*);
 
+/// [-1, +0, -]
+/// Cancels repositioning for this window. If the window is in the process of being repositioned by
+/// the user dragging it, that will be cancelled and no repositioning will take place.
+static int api_window_cancelreposition(lua_State*);
+
 /// [-2, +0, -]
 /// Sets an event handler for this window for reposition events. If the value is a function, it
 /// will be called with one parameter, that being a reposition event object. If the value is not a