SlimBlade Pro Middle Click: Defect or Normal?

A loud, crisp middle click on a new Kensington SlimBlade Pro is usually not a defect: this trackball has conspicuously clicky physical buttons, and “middle click” is merely the function assigned to one of them. Return or exchange it when the click is accompanied by duplicate inputs, missed presses, sticking, or a button that releases while you are still holding it.

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This diagnosis rests on published owner reports, a hands-on teardown, manufacturer documentation, and independent testing; no hands-on testing was performed for this article. No source used here publishes a calibrated sound-pressure measurement for the SlimBlade Pro’s buttons, so claims about loudness below are qualitative rather than invented dBA figures.

Three SlimBlade sounds that are easy to confuse

The SlimBlade Pro can produce three distinct noises, and only one comes from the middle-click switch.

The button clack: Pressing any of the four large button areas actuates a physical switch beneath the top shell. Multiple owners describe the stock buttons as loud or relatively resistant, including an owner report comparing them with conventional mouse buttons. A teardown likewise found physical switches beneath the buttons and replaced them specifically because their normal clicks were too loud—not because they were malfunctioning. That teardown also shows that opening the trackball requires removing seven concealed screws, disconnecting ribbon cables and desoldering components, so it is not a sensible diagnostic step for a new unit. See the SlimBlade Pro teardown.

The scrolling ticks: Twisting the ball clockwise or counter-clockwise produces deliberate audible feedback from a small internal buzzer. It is separate from the button switches. A reviewer heard these subtle ticks during twist-scrolling but no corresponding noise during ordinary ball movement, while the teardown physically identified the buzzer. The Gadgeteer’s hands-on review distinguishes scrolling from rolling noise. Hearing repeated ticks while twisting the ball therefore does not indicate a defective middle button.

A squeak while the ball moves: A rubbing or squeaking sound produced by rolling rather than clicking points toward the ball and its support bearings, not the middle-click switch. Remove loose dust from the ball cup and supports using the manufacturer’s cleaning guidance; do not spray lubricant, alcohol, or cleaner into a new trackball. If a newly cleaned unit still binds or squeaks severely, treat that as a separate return issue.

A 60-second check before returning it

The SlimBlade Pro does not have a uniquely constructed “middle-click button.” Kensington’s software lets you assign Middle Click to an individual button or to a two-button combination, which means the logical command can be moved without changing the hardware. The Kensington Konnect user guide documents the Buttons tab, individual-button selection, Middle Click assignment and per-button reset.

1. Open Kensington Konnect, select the SlimBlade Pro, then open Buttons. Note which physical corner currently carries Middle Click.
2. In an input-event viewer, make 20 slow, separate presses. A healthy switch should produce 20 button-down and 20 button-up events—no extras and no omissions. Where middle-click opens browser links in background tabs, 20 presses on one fixed link provide a simpler functional check.
3. Temporarily assign Middle Click to another corner. If the loud tone stays with the original physical corner, you are hearing that paddle and switch—not a special sound generated by the middle-click command.
4. Temporarily assign Left Click to the suspect corner and drag-select text for five seconds. A selection that drops before release exposes an intermittent switch or button-up fault.
5. Restore the original assignment with the button’s Reset control.

Run the same test over USB and one wireless mode only if the input events are unreliable. A physical clack will not be cured by changing connections, but duplicate or missing events that appear exclusively over one connection may indicate a radio, receiver, or software problem rather than a worn switch.

What actually counts as a defective switch

A different pitch by itself is weak evidence because the SlimBlade’s broad plastic paddles can resonate differently depending on where they are pressed. These behaviors are much stronger evidence of a faulty new unit:

• One deliberate press repeatedly creates two or more middle-click events.
• A press sometimes creates no event unless excessive force is applied.
• The button-down state ends while the paddle is still held.
• The paddle remains depressed, returns slowly, scrapes, or lacks a clear rebound.
• A loose internal rattle is present even when no button or ball is moving.
• One corner changes behavior after remapping while the other three remain reliable.

Do not confuse perceived on-screen delay with switch chatter. RTINGS independently measured the SlimBlade Pro’s maximum polling rate at 125Hz across all connection types after retesting and also found high click latency, particularly wirelessly. That limitation can make the pointer or click response feel sluggish on a high-refresh display, but it does not turn one clean input event into a broken switch. Read the RTINGS measurements and retest note.

SlimBlade Pro versus MX Ergo S

The Logitech MX Ergo S is not a direct silent replacement for the SlimBlade Pro’s middle click. Logitech’s published 80% reduction is a comparison of the left-click sound measured internally at one metre, and its product page describes six customizable buttons, USB-C charging and a 20-degree tilt. Logitech’s MX Ergo S specifications explain the claim. An independent reviewer further reports that the quieter treatment applies to the main left and right buttons, not all secondary controls. Digital Camera World’s MX Ergo S review notes that limitation.

That matters because middle click on the MX Ergo S is performed through its conventional scroll wheel. Buying it solely because “quiet clicks” sounds like a promise of a silent middle button would overread the specification.

The MX Ergo S also gets the comparison wrong for left-handed users and anyone specifically seeking a large finger-operated ball: it is a sculpted right-handed thumb trackball. It is the more relevant alternative when you already prefer thumb control and want substantially quieter primary clicking, not when twist-scrolling or ambidextrous operation caused you to choose the SlimBlade.

Keep it, exchange it, or change models

Keep the SlimBlade Pro when every press generates one clean event, the paddle rebounds immediately, and the only complaint is a sharp mechanical sound. Published reports and teardown evidence show that loud stock buttons are a design characteristic. Exchanging a healthy unit may produce another unit that sounds much the same.

Exchange or return it when the event test exposes double inputs, missed presses, early releases or physical sticking. Do that before opening the case or attempting a silent-switch modification. Kensington lists model K72080WW with a limited three-year warranty, providing a proper route when a functional fault appears after the seller’s return period. Kensington’s support page lists the specification and warranty.

Choose the MX Ergo S instead when right-handed thumb operation already suits you and overall desk noise—especially ordinary left and right clicking—is the deciding concern. Do not switch expecting its wheel press to inherit Logitech’s documented left-click reduction.

Neither trackball deserves a blanket skip. The SlimBlade Pro remains the stronger buy for ambidextrous finger control and twist-scrolling when its inputs test clean; the MX Ergo S is the narrower quieter-primary-click alternative for right-handed thumb-trackball users. A loud SlimBlade middle click alone is normal, but unreliable electrical behavior is an RMA case.