Deleting (many) points makes map slow

[ajpanton]

1. Search for a date range where you have a large-ish number of points close to each other, preferably in the exact same location to make the upcoming steps easier (for example from an inaccurate Wifi/Cellular source). Not so many that your browser struggles to render them. Like a day maybe.
2. Show points.
3. Start deleting them one by one. Lots of them.

After a while, everything becomes really slow. The popup window appears slower than before, not to mention if you accidentally move or zoom the map. The more points you delete, the slower everything becomes, to the point where it becomes unusable. Re-searching resets everything back to normal.

On my computer, by about 30 deletions, you start noticing a slowdown, and by 60, a re-search is a must to reset everything back to normal. Tested both with Firefox and Chrome.