Bugzilla

The problem occurs if you try to drag an image or selected text. When you start dragging, there is a "preview" image that appears near/under the mouse cursor, and with desktop zooming enabled it was initially positioned and sized incorrectly. Here's the specific STR that I used (as best I can remember):
1. Turn on apz.allow_zooming=true
2. Go to https://staktrace.com/kats/contact.php
3. Use desktop zooming to zoom in (I was using pinch gesture on macOS trackpad)
4. Place the mouse cursor over the captcha image (the one with the math question), mouse down, and move mouse. Verify that the drag preview image initially appears under the mouse, positioned where the original image is, and then moves around in sync with the mouse. Without these patches, the drag preview would initially appear somewhere else and then slide over to where the mouse cursor was. Also verify the size of the drag image matches the image as visible on the screen (zoomed in). Note that images that are extremely large do still get scaled down to save on memory, that is expected.
5. Repeat step 4 but with some text selection - select some text, and then drag it to get a drag preview image of the selection.

You can try this on a variety of pages with different images and text. Let me know if the STR are not clear or if you still have trouble reproducing the problem.

The problem occurs if you try to drag an image or selected text. When you start dragging, there is a "preview" image that appears near/under the mouse cursor, and with desktop zooming enabled it was initially positioned and sized incorrectly. Here's the specific STR that I used (as best I can remember):
1. Turn on apz.allow_zooming=true
2. Go to https://staktrace.com/kats/contact.php
3. Use desktop zooming to zoom in (I was using pinch gesture on macOS trackpad)
4. Place the mouse cursor over the captcha image (the one with the math question), press mouse button down, and move mouse. Verify that the drag preview image initially appears under the mouse, positioned where the original image is, and then moves around in sync with the mouse. Without these patches, the drag preview would initially appear somewhere else and then slide over to where the mouse cursor was. Also verify the size of the drag image matches the image as visible on the screen (zoomed in). Note that images that are extremely large do still get scaled down to save on memory, that is expected.
5. Repeat step 4 but with some text selection - select some text, and then drag it to get a drag preview image of the selection.

You can try this on a variety of pages with different images and text. Let me know if the STR are not clear or if you still have trouble reproducing the problem.