I cannot see a screenshot attached so could you upload it again?
Could you post here the minimal markup that reproduces the issue so I can actually investigate it if neither resolving any potential errors, nor reducing these properties to smaller values (you can simply remove them so they fall back to their defaults) helps?
Also, if you have some custom handlers on the link button (especially ones that are supposed to show a radtooltip) could you remove them to see if the automatic tooltips left alone work as expected?
Yet another point of interest is the browser you are having issues with - is it isolated to a certain browser, or is it happening across all of them?
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