When trying to x-out tags in the filtering mode, they are not always removal (this may be related to the order which they were uploaded to the site? Try using "עגנון" and "שיר מולחן" - there's no way to clear "שיר מולחן"). Either way, you can't x-out the last remaining tag, which means that the only way to clear it from your search is to reset the whole search.
When trying to x-out tags in the filtering mode, they are not always removal (this may be related to the order which they were uploaded to the site? Try using "עגנון" and "שיר מולחן" - there's no way to clear "שיר מולחן"). Either way, you can't x-out the last remaining tag, which means that the only way to clear it from your search is to reset the whole search.