I like my new Surface Pro 3. Things were working fine and all of a sudden, the cursor would disappear. I just have the Type Cover and a memory card installed: no other hardware. Narrowing down the issue: if I move my finger in circles on the trackpad to make the cursor move in small circles in the same area on a web page in IE, or Word or Visual Studio, the cursor disappears in a few seconds. I made sure my finger does not go anywhere near the edge of the trackpad and the mouse stays within the same window over a blank space (so that the WM_MOUSEMOVE is handled consistently). If I move my finger a little more, the cursor will come back, but after perhaps closing the window I was working on.

I used SPY++ (installed with Visual Studio) to track WM_* messages and saw that hundreds of MOUSEMOVE messages appear as expected, but stopped appearing when the cursor disappeared.

This made it very difficult to do any productive work. I tried disconnect/reconnect the keyboard multiple times, rebooting/shutting down, etc. with no luck. After the cursor disappears, it can come back with subtle trackpad movements, at the top right corner of the screen. This is really annoying because touching the trackpad sends a WM_MouseDown on a maximized window’s “X” button, closing that window.

My Surface RT and the Surface Pro 1 never showed this problem.

I was quite disappointed and wondered how I would be able to return/exchange it, having purchased it at full retail price.

I brought it to my office the next day and it worked fine. I tried lots of ways to try to reproduce the problem, but it continued to behave properly. I eventually thought it must have something to do with the environment.

When I put it on the table at home, it didn’t work. When I put it on my lap, it worked fine. Wow. I used a lead lined bag (used for shielding camera film  (remember that?) from x-rays at airports) which I’d flattened and use as a shield between the Surface and the tabletop, and it seemed to fix the problem a bit, but not quite. As soon as I move the Surface off the table the mouse works fine.

If I put the Surface on my lap, the cursor never misbehaves. <whew>

I tried the Surface Pro 1 Type Cover with the Surface Pro 3 on the glass table, and the problem does occur, but less often.

This is a table with “Micro etched matte tempered 10mm glass”: there was a metal bar right under the table, so I tried various positions of the Surface on the table, even hanging it over the table edge.

Then I thought maybe it wasn’t the table, but something near the table. I noticed that the fluorescent light on the table might have something to do with it. Sure enough, when I turned off the light, everything worked just fine!

When I thought about it, the Surface Pro 3 comes with a pen and works as a digitizing tablet as well. The Surface detects the presence of a pen without any physical contact, so it must be some sort of electromagnetic field. When the fluorescent light was on, it was emitting a field that seemed to the Surface to be the pen. The cursor would just move toward the light (just as phototropic plants do J). When the pen is above the corner of the screen (both left and right), the cursor turns into a little point. As I test it now (I’m writing this on the SP3), the cursor goes to the corner of the screen only when the pen is about an inch from the screen. The light was typically at least 8 inches from the screen, so it must have been a fairly powerful field.

So there was nothing wrong at all: I just needed to stay away from the light!