1. Create a new file and name it test.less.
2. Paste the following content to the new file and save it.

aside li {
    overflow: hidden;
    margin-bottom: 1px;
}
li.categoria {
    padding: 0 0 5px 0;
    border-bottom: 1px solid #09b7d6;
}
li:nth-last-child(-n+4) {
    float: left;
}
input.toggle {
    display: none;
}
input.toggle + label {
    cursor: pointer;
    display: block;
    text-indent: 28px;
    vertical-align: middle;
    line-height: 42px;
}
input.toggle:checked + label {
    background: #5b6669;
}

1. Relaunch Brackets and try to select test.less in the project tree.

Result: You can't. If it is already in the working set, it shows up nothing in the editor. And if you start selecting another file in the project tree, either the file content shows up in the editor somewhere in the middle of the page. ie. line number 1 starts somewhere in the middle of the window and leaving some spaces above. And if you try to click test.less in the project tree, the selection highlight goes to the file above test.less.