René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Minor ticklabels are missing at positions of major ticks.","articleBody":"\u003c!--To help us understand and resolve your issue, please fill out the form to the best of your ability.--\u003e\r\n\u003c!--You can feel free to delete the sections that do not apply.--\u003e\r\n\r\n### Bug report\r\n\r\n**Bug summary**\r\n\r\nMinor ticklabels are missing at positions of major ticks.\r\n\r\n**Code for reproduction**\r\n\r\n```\r\nimport numpy as np\r\nimport matplotlib.dates as mdates\r\nimport matplotlib.pyplot as plt\r\n\r\nt = np.arange(\"2018-11-03\", \"2018-11-06\", dtype=\"datetime64\")\r\nx = np.random.rand(len(t))\r\n\r\nfig, ax = plt.subplots()\r\nax.plot(t,x)\r\n\r\nax.xaxis.set_major_locator(mdates.DayLocator())\r\nax.xaxis.set_major_formatter(mdates.DateFormatter('\\n%a'))\r\n\r\nax.xaxis.set_minor_locator(mdates.HourLocator((0,6,12,18)))\r\nax.xaxis.set_minor_formatter(mdates.DateFormatter('%H:%M'))\r\n\r\nplt.show()\r\n```\r\n\r\n**Actual outcome**\r\n\r\nThe above code run with current master produces\r\n\r\n![image](https://user-images.githubusercontent.com/23121882/53986707-332eaf80-411f-11e9-9d0b-4d1df4bae02a.png)\r\n\r\nThe minor ticklabels showing the `00:00` hours are missing.\r\n\r\n**Expected outcome**\r\n\r\nThe expected outcome would be the same as when running the code with matplotlib 3.0.2 or below:\r\n\r\n![image](https://user-images.githubusercontent.com/23121882/53986815-7b4dd200-411f-11e9-84d2-e820792bf6ce.png)\r\n\r\nI would expect to see the hours throughout.\r\n\r\n**Matplotlib version**\r\n\u003c!--Please specify your platform and versions of the relevant libraries you are using:--\u003e\r\n  * Operating system: Win8\r\n  * Matplotlib version: master\r\n  * Matplotlib backend (`print(matplotlib.get_backend())`): any\r\n  * Python version: 3.6\r\n\r\n","author":{"url":"https://github.com/ImportanceOfBeingErnest","@type":"Person","name":"ImportanceOfBeingErnest"},"datePublished":"2019-03-07T20:27:00.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":25},"url":"https://github.com/13618/matplotlib/issues/13618"}