fix: window position drift on Windows multi-monitor setups

On Windows with multiple displays, both the NethLink and PhoneIsland
windows would gradually shift position each time they were shown/hidden.
NethLink drifted 1-2px upward per cycle, while PhoneIsland drifted on
both axes by several pixels, eventually disappearing off-screen.

Root causes:
- PhoneIsland: showPhoneIsland() made two partial setBounds() calls
  (first width/height only via resize(), then x/y only), each triggering
  DPI scaling rounding on Windows. Combined into a single setBounds()
  call with the full rectangle.
- NethLink: the getBounds()/setBounds() save-restore cycle accumulated
  fractional pixel rounding errors from DPI conversions. Added
  Math.round() on all saved coordinates.
- Drag handler: used getContentSize() (inner area excluding title bar
  and borders) but passed the result to setBounds() which expects outer
  window dimensions. Replaced with getBounds() for correct size values.

These issues only manifested on Windows with multiple monitors due to
per-monitor DPI awareness coordinate translation. macOS, Linux, and
single-monitor Windows setups were unaffected.

Author: edospadoni

src/main/classes/controllers/PhoneIslandController.ts

@@ -22,9 +22,17 @@ export class PhoneIslandController {
       const { w, h } = size
       const window = this.window.getWindow()
       if (window) {
-        const bounds = window.getBounds()
-        if (bounds.height !== h || bounds.width !== w) {
-          window.setBounds({ width: w, height: h })
+        const currentBounds = window.getBounds()
+        if (currentBounds.height !== h || currentBounds.width !== w) {
+          // Use saved position as authoritative source to prevent DPI drift accumulation.
+          // getBounds() on Windows multi-monitor returns DPI-converted values that drift
+          // on each setBounds/getBounds roundtrip. The saved position is the user's intended
+          // position and should always be used instead.
+          const savedPosition = AccountController.instance.getAccountPhoneIslandPosition()
+          const x = savedPosition ? savedPosition.x : currentBounds.x
+          const y = savedPosition ? savedPosition.y : currentBounds.y
+          const newBounds = { x, y, width: w, height: h }
+          window.setBounds(newBounds)
           PhoneIslandWindow.currentSize = { width: w, height: h }
         }
         //make sure the size is equal to [0,0] when you want to close the phone island, otherwise the size will not close and will generate slowness problems.
@@ -48,8 +56,10 @@ export class PhoneIslandController {
     try {
       const window = this.window.getWindow()
       if (window) {
+        const { w, h } = size
+        // Target bounds to apply after show() to override any WM adjustments
+        let targetBounds: Electron.Rectangle | undefined
 
-        this.resize(size)
         if (process.platform !== 'linux') {
           const phoneIslandPosition = AccountController.instance.getAccountPhoneIslandPosition()
           if (phoneIslandPosition) {
@@ -59,21 +69,37 @@ export class PhoneIslandController {
                 result ||
                 (phoneIslandPosition.x >= area.x &&
                   phoneIslandPosition.y >= area.y &&
-                  (phoneIslandPosition.x + size.w) < (area.x + area.width) &&
-                  (phoneIslandPosition.y + size.h) < (area.y + area.height))
+                  (phoneIslandPosition.x + w) < (area.x + area.width) &&
+                  (phoneIslandPosition.y + h) < (area.y + area.height))
               )
             }, false)
             if (isPhoneIslandOnDisplay) {
-              window?.setBounds({ x: phoneIslandPosition.x, y: phoneIslandPosition.y }, false)
+              targetBounds = { x: phoneIslandPosition.x, y: phoneIslandPosition.y, width: w, height: h }
+              window.setBounds(targetBounds, false)
+              PhoneIslandWindow.currentSize = { width: w, height: h }
             } else {
-              window?.center()
+              this.resize(size)
+              window.center()
             }
           }
           else {
-            window?.center()
+            this.resize(size)
+            window.center()
           }
         } else {
-          window?.center()
+          this.resize(size)
+          window.center()
+        }
+
+        if (h === 0 && w === 0) {
+          window.hide()
+        } else if (!window.isVisible() && !this.isWarmingUp) {
+          window.show()
+          window.setAlwaysOnTop(true, 'screen-saver')
+          // Re-assert position after show/setAlwaysOnTop to override any WM/DPI adjustment
+          if (targetBounds) {
+            window.setBounds(targetBounds, false)
+          }
         }
       }
     } catch (e) {
@@ -86,10 +112,18 @@ export class PhoneIslandController {
       const window = this.window.getWindow()
       const phoneIslandBounds = window?.getBounds()
       if (phoneIslandBounds) {
-        AccountController.instance.setAccountPhoneIslandPosition({
-          x: phoneIslandBounds.x,
-          y: phoneIslandBounds.y
-        })
+        const savedPosition = AccountController.instance.getAccountPhoneIslandPosition()
+        // Only save if the user actually moved the window (not DPI rounding drift).
+        // DPI rounding on Windows multi-monitor typically shifts by 1-3px per cycle.
+        const DPI_DRIFT_THRESHOLD = 15
+        if (!savedPosition ||
+          Math.abs(phoneIslandBounds.x - savedPosition.x) > DPI_DRIFT_THRESHOLD ||
+          Math.abs(phoneIslandBounds.y - savedPosition.y) > DPI_DRIFT_THRESHOLD) {
+          AccountController.instance.setAccountPhoneIslandPosition({
+            x: phoneIslandBounds.x,
+            y: phoneIslandBounds.y
+          })
+        }
       }
       debouncer('hide', () => window?.hide(), 250)
     } catch (e) {

src/main/classes/windows/NethLinkWindow.ts

@@ -70,6 +70,7 @@ export class NethLinkWindow extends BaseWindow {
 
   show(): void {
     try {
+      let targetBounds: Electron.Rectangle | undefined
       const accountBounds = AccountController.instance.getAccountNethLinkBounds()
       if (accountBounds) {
         const isAccountBoundsOnDisplay = screen.getAllDisplays().reduce((result, display) => {
@@ -83,6 +84,7 @@ export class NethLinkWindow extends BaseWindow {
           )
         }, false)
         if (isAccountBoundsOnDisplay) {
+          targetBounds = accountBounds
           this._window?.setBounds(accountBounds, false)
         } else {
           this._setBounds()
@@ -94,6 +96,10 @@ export class NethLinkWindow extends BaseWindow {
       this._window?.setVisibleOnAllWorkspaces(true)
       this._window?.focus()
       this._window?.setVisibleOnAllWorkspaces(false)
+      // Re-assert position after show/focus to override any WM/DPI adjustment on Windows
+      if (targetBounds) {
+        this._window?.setBounds(targetBounds, false)
+      }
     }
     catch (e: any) {
       if (e.message === 'Object has been destroyed') {
@@ -107,7 +113,7 @@ export class NethLinkWindow extends BaseWindow {
 
   hide(..._args: any): void {
     try {
-      this.saveBounds()
+      this.saveBoundsIfMoved()
       this._window?.hide()
     } catch (e) {
       Log.warning('during hiding the NethLinkWindow:', e)
@@ -119,11 +125,27 @@ export class NethLinkWindow extends BaseWindow {
     AccountController.instance.setAccountNethLinkBounds(nethlinkBounds)
   }
 
+  // Only save if the user actually moved/resized the window (not DPI rounding drift).
+  // DPI rounding on Windows multi-monitor typically shifts by 1-3px per cycle.
+  private saveBoundsIfMoved() {
+    const currentBounds = this._window?.getBounds()
+    if (!currentBounds) return
+    const savedBounds = AccountController.instance.getAccountNethLinkBounds()
+    const DPI_DRIFT_THRESHOLD = 15
+    if (!savedBounds ||
+      Math.abs(currentBounds.x - savedBounds.x) > DPI_DRIFT_THRESHOLD ||
+      Math.abs(currentBounds.y - savedBounds.y) > DPI_DRIFT_THRESHOLD ||
+      Math.abs(currentBounds.width - savedBounds.width) > DPI_DRIFT_THRESHOLD ||
+      Math.abs(currentBounds.height - savedBounds.height) > DPI_DRIFT_THRESHOLD) {
+      this.saveBounds(currentBounds)
+    }
+  }
+
   buildWindow(): void {
     super.buildWindow()
     this._window?.on('hide', this.toggleVisibility)
     this._window?.on('moved', () => {
-      debouncer('onMoveNethLinkWindow', () => this.saveBounds(), 1000)
+      debouncer('onMoveNethLinkWindow', () => this.saveBoundsIfMoved(), 1000)
     })
     this._window?.on('show', this.toggleVisibility)
     this._window?.on('closed', this.toggleVisibility)

src/main/lib/ipcEvents.ts

@@ -213,12 +213,12 @@ export function registerIpcEvents() {
               height
             }, false)
           } else {
-            const [w, h] = window.getContentSize()
+            const bounds = window.getBounds()
             window.setBounds({
               x: newX,
               y: newY,
-              width: w,
-              height: h
+              width: bounds.width,
+              height: bounds.height
             }, false)
           }
         }