If there are lots of issues after the compilation failure, the Issues list becomes very slow to operate. For example, after compiling my project the linker produced 3154 issues (errors about missing symbols), and every click on the issues list results in ~12 seconds delay with a CPU core loaded 100%, QtCreator unresponsive.

Scrolling the list with mouse wheel or scroll bar is fast. Switching to other planes (e.g. compiler output) and back is fast. But if I click on an item in the list QtCreator becomes unresponsive.