<p dir="auto">Transparent window will not fill screen when max.<br>
It will keep a gap between window border and screen edge.</p>
<p dir="auto"><a target="_blank" rel="noopener noreferrer nofollow" href="https://cloud.githubusercontent.com/assets/3841135/7603152/e2034e22-f960-11e4-93ac-10a30ea0478e.png"><img src="https://cloud.githubusercontent.com/assets/3841135/7603152/e2034e22-f960-11e4-93ac-10a30ea0478e.png" alt="" style="max-width: 100%;"></a><br>
This is a top-right corner of my test window,<br>
the white and light gray border is gap.</p>
<p dir="auto"><strong>OS: Windows 8.1</strong><br>
<strong>electron: v0.26.0</strong></p>
<p dir="auto">Code:<br>
<strong>index.html</strong></p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="&lt;!DOCTYPE html&gt;
&lt;html&gt;
&lt;head&gt;
    &lt;title&gt;test&lt;/title&gt;
    &lt;style type=&quot;text/css&quot;&gt;
        html, body {
            margin: 0;
            padding: 0;
            width: 100%;
            height: 100%;
            background: #000;
        }
    &lt;/style&gt;
&lt;/head&gt;
&lt;body style=&quot;-webkit-user-select:none;-webkit-app-region:drag&quot;&gt;&lt;/body&gt;
&lt;/html&gt;"><pre class="notranslate"><code class="notranslate">&lt;!DOCTYPE html&gt;
&lt;html&gt;
&lt;head&gt;
    &lt;title&gt;test&lt;/title&gt;
    &lt;style type="text/css"&gt;
        html, body {
            margin: 0;
            padding: 0;
            width: 100%;
            height: 100%;
            background: #000;
        }
    &lt;/style&gt;
&lt;/head&gt;
&lt;body style="-webkit-user-select:none;-webkit-app-region:drag"&gt;&lt;/body&gt;
&lt;/html&gt;
</code></pre></div>
<p dir="auto"><strong>app.js</strong></p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="var app = require(&quot;app&quot;);
var browserWindow = require(&quot;browser-window&quot;);

var window = null;

app.on(&quot;window-all-closed&quot;, function () {
    if (app.listeners(&quot;window-all-closed&quot;).length == 1)
        app.quit();
});

app.on(&quot;ready&quot;, function () {
    window = new browserWindow({
        &quot;width&quot;: 600, &quot;height&quot;: 400,
        &quot;frame&quot;: false, &quot;transparent&quot;: true,
        &quot;node-integration&quot;: true
    });
    window.loadUrl(&quot;file://&quot; + __dirname + &quot;/index.html&quot;);
    window.on(&quot;closed&quot;, function () {
        window = null;
    });
});"><pre class="notranslate"><code class="notranslate">var app = require("app");
var browserWindow = require("browser-window");

var window = null;

app.on("window-all-closed", function () {
    if (app.listeners("window-all-closed").length == 1)
        app.quit();
});

app.on("ready", function () {
    window = new browserWindow({
        "width": 600, "height": 400,
        "frame": false, "transparent": true,
        "node-integration": true
    });
    window.loadUrl("file://" + __dirname + "/index.html");
    window.on("closed", function () {
        window = null;
    });
});
</code></pre></div>
<p dir="auto">run the code, and set the window max:<br>
<a target="_blank" rel="noopener noreferrer nofollow" href="https://cloud.githubusercontent.com/assets/3841135/7742269/b6542c64-ffbf-11e4-820f-a50c43a93f10.png"><img src="https://cloud.githubusercontent.com/assets/3841135/7742269/b6542c64-ffbf-11e4-820f-a50c43a93f10.png" alt="image" style="max-width: 100%;"></a></p>
<p dir="auto">On Windows 8.1 the transparency feature works fine until the moment when a window becomes maximized. After that it become to look like this(notice the frame style and also it looks like the additive blending mode is applied):<br>
<a target="_blank" rel="noopener noreferrer nofollow" href="https://cloud.githubusercontent.com/assets/2578826/7640670/50a9d29c-fa8d-11e4-88e6-7d02cad4b534.png"><img src="https://cloud.githubusercontent.com/assets/2578826/7640670/50a9d29c-fa8d-11e4-88e6-7d02cad4b534.png" alt="transparency_issue" style="max-width: 100%;"></a><br>
Is this bug related to the specific version of Windows(haven't checked it on earlier versions)? I've tried to look into the Electron sources but can't find entry points where it works with DWM...<br>
P.S.<br>
I have just checked this on Windows 7, same behaviour.</p>