This bug was filed from the Socorro interface and is report bp-acb61cf5-affc-45b2-a507-c993d2110913 . ============================================================= Build Identifier: http://hg.mozilla.org/mozilla-central/rev/da2f5b63ba1e Mozilla/5.0 (Windows NT 6.1; WOW64; rv:9.0a1) Gecko/20110913 Firefox/9.0a1 ID:20110913030846 Reproducible: Always Steps to Reproduce for "en-US" localized build: 1. Open Firefox with clean profile 2. Install "DOM Inspector"( https://addons.mozilla.org/ja/firefox/addon/dom-inspector-6622/ ) 3. Restart Browser 4. Open any page ,ore than 20-30 tabs 5. Open "Add-ons Manager"(Ctrl+Shift+A) 6. Select "Get Add-ons" 7. Open "DOM Inspector"( Ctrl+Shift+I ) 8. Move window of "DOM Inspector" to lower part of screen (i.e. the following menupopup touch the screen bottom edge) 9. "File" > "Inspect Content Document" > mouse hover "Discover Add-ons" (so that tooltip pops up) 10. Repeat step 9. Actual Results: Step 9: Black rectangle tooltip appears. Step 10: Browser will crash Expected Results: No Crash Graphics Adapter Description: ATI Radeon HD 4300/4500 Series Vendor ID: 1002 Device ID: 954f Adapter RAM: 512 Adapter Drivers: aticfx64 aticfx64 aticfx32 aticfx32 atiumd64 atidxx64 atiumdag atidxx32 atiumdva atiumd6a atitmm64 Driver Version: 8.881.0.0 Driver Date: 7-28-2011 Adapter RAM (GPU #2): Unknown Adapter Drivers (GPU #2): Unknown Direct2D Enabled: true DirectWrite Enabled: true (6.1.7601.17563) ClearType Parameters: Gamma: 2200 Pixel Structure: RGB ClearType Level: 100 Enhanced Contrast: 200 WebGL Renderer: Google Inc. -- ANGLE (ATI Radeon HD 4300/4500 Series ) -- OpenGL ES 2.0 (ANGLE 0.0.0.740) GPU Accelerated Windows: 1/1 Direct3D 10

Spelling error in Step 4. s/,ore/more/

I cannot reproduce anymore in Firefox10ESR and Firefox13 and later with DOMi 2.0.12 .