By Kasper Jade and Katie Marsal

Published: 04:40 PM EST

Internally, Apple has acknowledged a problem with its newly designed scrolling TrackPad currently shipping with its new PowerBook G4 models.

Shares of Synaptics, Inc. tanked over 20% in early February after reports revealed that Apple had ditched the interface solution designer as its supplier of TrackPads for the new PowerBook G4 series. Historically, Apple had tapped Synpatics for all of its laptop-based TrackPad solutions, starting with the PowerBook and later the iBook.

Instead, the new Apple laptops made their debut with a proprietary TrackPad solution, which the Mac maker internally sourced. But was it the right move to go it alone on the new TrackPad design? That's the question Apple insiders are left to ponder as the company's first PowerBook woes of the new year have surfaced.

In short, the performance of Apple's new patent-pending scrolling TrackPads, which lets users scroll through large documents by touching the pad with two fingers instead of one, has been inconsistent and unacceptable to some early adopters. Reports vary, but the most prominent issue appears to be random and erratic behavior of the TrackPads on the new 12 and 15-inch PowerBooks. A variety of other complaints include irritably slow mouse tracking, customers receiving shocks from the PowerBooks due to static electricity and TrackPads failing to respond at all for short periods of time.

MacInTouch, a website which documents customer experiences with new Apple products, has been compiling reports from consumers dissatisfied with the new TrackPads. "I’ve had six PowerBooks since the PowerBook 100, and I can definitely state that my new PowerBook G4 15" has a dysfunctional trackpad," said one of the sites readers. Another reader complained that even after her new PowerBook had been in Apple's repair depot for two weeks it returned with a TrackPad that freezes or is 'extremely slow.'

According to sources, the fury of reports has caused concern for Apple, which earlier this week reportedly published an alert bulletin to its retail stores detailing the problem, but asking employees not to acknowledge the issues to customers. Sources said Apple is attempting to isolate and correct problems with the new TrackPad by pulling back some PowerBook models, which has constrained supplies of the laptops at retail stores that would normally be working off 25 days of inventory at this time of year.

So far there have been little to no reports of TrackPad issues on the 17-inch PowerBooks, which remain in good supply. Customers who are experiencing problems with the TrackPad on their new PowerBooks should seek a replacement or repair from their local Apple retail store.

Synaptics, by the way, continues to supply Apple with scroll-wheels for its ubiquitous iPod music players.