Gmail has a hidden preview window in which you can see an e-mail with two windows – just like in Outlook and other desktop e-mail clients. To enable them on the web and choose a horizontal or vertical split, follow these steps.
First, go to your Gmail Inbox. Click on the settings window and then on "Settings".
Select the Advanced tab.
tab The preview The window option is down. Select "Activate" and then click "Save changes".
You will be taken back to the Inbox, where a new button to toggle the split pane is visible next to the Settings Kog.
This is a bite, so we call it a "switch preview".
When you click the arrow In addition to the preview switching button, you can choose to split the preview area vertically or horizontally.
The vertical section mode means that the preview area is displayed in the open window on the right side of the screen with your emails on the left side.
This is especially useful if you have a widescreen monitor. The Split Horizontally mode means that the preview window at the bottom of your Inbox will open with the emails at the top.
This is especially useful if you have a square monitor or you are using a widescreen monitor rotated 90 °. However you prefer the preview area, you can move the border left or right or up and down to resize it. If you switch between vertical and horizontal, the selection of all emails currently displayed in the preview area is disabled, so you must re-select the email to preview the email. You can click the switch preview button to toggle between showing and hiding the preview window by clicking No Split on the toggle preview menu. The switch preview button is not removed. It only switches between showing and hiding the preview window. If you want to completely remove the preview switching option, go back to Settings> Advanced and deactivate the preview area.
If the preview area is enabled, another option is available. Go to Settings, click on "Settings", and on the "General" tab a new option for the preview window will be displayed (about 2/3 of the downhill path).
 This option allows you to specify when a mail is marked as read when you display it in the preview pane. The options are:
- After 1 second
- After 3 seconds (This is the default setting)
- After 20 seconds
Select the desired option and scroll down and click "Save changes" to return to the Inbox. This setting only has an effect if you have activated the preview window and have split either Vertical or Horizontal. If you disable the preview window function, this option is no longer displayed.
Now you can preview your emails as if you were using a desktop email client. Unfortunately, this option is not yet available in the Gmail mobile app – which could be useful for tablets. However, you can view Gmail from a browser on your mobile device if this preview window is a critical factor for you.